FA-59636 / Subscription proration billing / Open access

Annual plan proration across leap years: exclusive range end · case 01

Every prorated range is billed one day too many.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The exclusive end date is treated as inclusive.

VERIFIED REPAIR

Restore the contract rule at the exclusive range end step: use `t = min(datetime.date(*x['to']), e)`.

Unsuccessful approach: The attempt drops the extra day but no longer clips the range to the term end.

Case contract

Input {price, start (annual term start), from, to (exclusive)}. The term is [start, same date next year); a Feb 29 start ends on Mar 1. The requested range is clipped to the term; days = max(0, clipped length). Amount = price*days/term_days half-up. Return [term_days, amount].

Why this case matters

Annual terms have 365 or 366 days depending on whether they contain Feb 29, which changes the daily rate.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import datetime
import calendar
N = 1
observations = []
def solve(x):
    s = datetime.date(*x['start'])
    try:
        e = s.replace(year=s.year + 1)
    except ValueError:
        e = datetime.date(s.year + 1, 3, 1)
    f = max(datetime.date(*x['from']), s)
    t = min(datetime.date(*x['to']) + datetime.timedelta(days=1), e)
    days = max(0, (t - f).days)
    total = (e - s).days
    return [total, (x['price'] * days * 2 + total) // (2 * total)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression', {'price': 119900, 'start': [2022, 1, 5], 'from': [2022, 2, 1], 'to': [2022, 5, 13]}, [365, 33178]), ('regression', {'price': 617594, 'start': [2024, 4, 7], 'from': [2024, 5, 22], 'to': [2024, 7, 8]}, [365, 79526]), ('partial-repair probe', {'price': 36600, 'start': [2023, 6, 28], 'from': [2024, 5, 21], 'to': [2024, 9, 14]}, [366, 3800]), ('partial-repair probe', {'price': 401416, 'start': [2025, 2, 14], 'from': [2026, 1, 26], 'to': [2026, 2, 15]}, [365, 20896]), ('normal control', {'price': 100385, 'start': [2025, 10, 15], 'from': [2026, 10, 7], 'to': [2026, 10, 15]}, [365, 2200]), ('normal control', {'price': 36600, 'start': [2023, 12, 24], 'from': [2023, 12, 9], 'to': [2023, 12, 10]}, [366, 0]), ('normal control', {'price': 400202, 'start': [2020, 2, 29], 'from': [2020, 2, 19], 'to': [2020, 2, 18]}, [366, 0]), ('normal control', {'price': 547591, 'start': [2022, 5, 7], 'from': [2022, 12, 9], 'to': [2022, 12, 7]}, [365, 0])], [('regression', {'price': 617594, 'start': [2024, 4, 7], 'from': [2024, 5, 22], 'to': [2024, 7, 8]}, [365, 79526]), ('regression', {'price': 36600, 'start': [2024, 1, 24], 'from': [2024, 4, 28], 'to': [2024, 5, 27]}, [366, 2900]), ('partial-repair probe', {'price': 36600, 'start': [2023, 7, 11], 'from': [2024, 5, 20], 'to': [2024, 7, 20]}, [366, 5200]), ('partial-repair probe', {'price': 36600, 'start': [2023, 4, 2], 'from': [2024, 2, 21], 'to': [2024, 5, 8]}, [366, 4100]), ('normal control', {'price': 36500, 'start': [2024, 8, 1], 'from': [2025, 7, 3], 'to': [2025, 8, 1]}, [365, 2900]), ('normal control', {'price': 119900, 'start': [2025, 2, 27], 'from': [2026, 3, 9], 'to': [2026, 3, 7]}, [365, 0]), ('normal control', {'price': 119900, 'start': [2025, 5, 10], 'from': [2025, 11, 11], 'to': [2025, 11, 9]}, [365, 0]), ('normal control', {'price': 36500, 'start': [2022, 7, 6], 'from': [2022, 6, 17], 'to': [2022, 7, 2]}, [365, 0])], [('regression', {'price': 36600, 'start': [2024, 1, 24], 'from': [2024, 4, 28], 'to': [2024, 5, 27]}, [366, 2900]), ('regression', {'price': 119900, 'start': [2025, 7, 19], 'from': [2025, 8, 25], 'to': [2026, 1, 13]}, [365, 46318]), ('partial-repair probe', {'price': 36500, 'start': [2024, 2, 29], 'from': [2025, 1, 6], 'to': [2025, 5, 17]}, [366, 5385]), ('partial-repair probe', {'price': 36500, 'start': [2024, 6, 2], 'from': [2025, 2, 2], 'to': [2025, 7, 10]}, [365, 12000]), ('normal control', {'price': 36500, 'start': [2023, 9, 5], 'from': [2024, 8, 17], 'to': [2024, 9, 5]}, [366, 1895]), ('normal control', {'price': 36500, 'start': [2025, 2, 5], 'from': [2025, 6, 6], 'to': [2025, 6, 1]}, [365, 0]), ('normal control', {'price': 108823, 'start': [2025, 11, 11], 'from': [2026, 6, 23], 'to': [2026, 6, 21]}, [365, 0]), ('normal control', {'price': 36600, 'start': [2025, 7, 27], 'from': [2026, 7, 12], 'to': [2026, 7, 11]}, [365, 0])], [('regression', {'price': 119900, 'start': [2025, 7, 19], 'from': [2025, 8, 25], 'to': [2026, 1, 13]}, [365, 46318]), ('regression', {'price': 975972, 'start': [2023, 4, 12], 'from': [2023, 10, 30], 'to': [2024, 1, 23]}, [366, 226660]), ('partial-repair probe', {'price': 36500, 'start': [2023, 5, 7], 'from': [2024, 4, 18], 'to': [2024, 10, 6]}, [366, 1895]), ('partial-repair probe', {'price': 835323, 'start': [2022, 3, 25], 'from': [2023, 1, 26], 'to': [2023, 6, 21]}, [365, 132736]), ('normal control', {'price': 971485, 'start': [2023, 1, 17], 'from': [2023, 3, 30], 'to': [2023, 3, 29]}, [365, 0]), ('normal control', {'price': 36500, 'start': [2025, 7, 17], 'from': [2025, 6, 28], 'to': [2025, 6, 28]}, [365, 0]), ('normal control', {'price': 119900, 'start': [2024, 12, 22], 'from': [2025, 11, 10], 'to': [2025, 11, 8]}, [365, 0]), ('normal control', {'price': 119900, 'start': [2024, 2, 26], 'from': [2025, 2, 15], 'to': [2025, 2, 12]}, [366, 0])], [('regression', {'price': 975972, 'start': [2023, 4, 12], 'from': [2023, 10, 30], 'to': [2024, 1, 23]}, [366, 226660]), ('regression', {'price': 36500, 'start': [2025, 4, 22], 'from': [2025, 10, 5], 'to': [2026, 2, 9]}, [365, 12700]), ('partial-repair probe', {'price': 36600, 'start': [2023, 1, 26], 'from': [2023, 10, 15], 'to': [2024, 3, 11]}, [365, 10328]), ('partial-repair probe', {'price': 36500, 'start': [2023, 12, 16], 'from': [2024, 10, 29], 'to': [2025, 3, 10]}, [366, 4787]), ('normal control', {'price': 119900, 'start': [2022, 6, 19], 'from': [2022, 10, 26], 'to': [2022, 10, 23]}, [365, 0]), ('normal control', {'price': 36500, 'start': [2024, 5, 30], 'from': [2025, 2, 16], 'to': [2025, 2, 12]}, [365, 0]), ('normal control', {'price': 100385, 'start': [2025, 10, 15], 'from': [2026, 10, 7], 'to': [2026, 10, 15]}, [365, 2200]), ('normal control', {'price': 36600, 'start': [2023, 12, 24], 'from': [2023, 12, 9], 'to': [2023, 12, 10]}, [366, 0])]]
for i, (label, args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (label, i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression 0	`[365, 33506]`	`[365, 33178]`	Failed
regression 1	`[365, 81218]`	`[365, 79526]`	Failed
partial-repair probe 2	`[366, 3800]`	`[366, 3800]`	Passed
partial-repair probe 3	`[365, 20896]`	`[365, 20896]`	Passed
normal control 4	`[365, 2200]`	`[365, 2200]`	Passed
normal control 5	`[366, 0]`	`[366, 0]`	Passed
normal control 6	`[366, 0]`	`[366, 0]`	Passed
normal control 7	`[365, 0]`	`[365, 0]`	Passed

SHA-256 / 75bb570fb10f05879060b65a1e1afc0f3598befdb598833659b10403dbe991f8

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import datetime
import calendar
N = 1
observations = []
def solve(x):
    s = datetime.date(*x['start'])
    try:
        e = s.replace(year=s.year + 1)
    except ValueError:
        e = datetime.date(s.year + 1, 3, 1)
    f = max(datetime.date(*x['from']), s)
    t = datetime.date(*x['to'])
    days = max(0, (t - f).days)
    total = (e - s).days
    return [total, (x['price'] * days * 2 + total) // (2 * total)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression', {'price': 119900, 'start': [2022, 1, 5], 'from': [2022, 2, 1], 'to': [2022, 5, 13]}, [365, 33178]), ('regression', {'price': 617594, 'start': [2024, 4, 7], 'from': [2024, 5, 22], 'to': [2024, 7, 8]}, [365, 79526]), ('partial-repair probe', {'price': 36600, 'start': [2023, 6, 28], 'from': [2024, 5, 21], 'to': [2024, 9, 14]}, [366, 3800]), ('partial-repair probe', {'price': 401416, 'start': [2025, 2, 14], 'from': [2026, 1, 26], 'to': [2026, 2, 15]}, [365, 20896]), ('normal control', {'price': 100385, 'start': [2025, 10, 15], 'from': [2026, 10, 7], 'to': [2026, 10, 15]}, [365, 2200]), ('normal control', {'price': 36600, 'start': [2023, 12, 24], 'from': [2023, 12, 9], 'to': [2023, 12, 10]}, [366, 0]), ('normal control', {'price': 400202, 'start': [2020, 2, 29], 'from': [2020, 2, 19], 'to': [2020, 2, 18]}, [366, 0]), ('normal control', {'price': 547591, 'start': [2022, 5, 7], 'from': [2022, 12, 9], 'to': [2022, 12, 7]}, [365, 0])], [('regression', {'price': 617594, 'start': [2024, 4, 7], 'from': [2024, 5, 22], 'to': [2024, 7, 8]}, [365, 79526]), ('regression', {'price': 36600, 'start': [2024, 1, 24], 'from': [2024, 4, 28], 'to': [2024, 5, 27]}, [366, 2900]), ('partial-repair probe', {'price': 36600, 'start': [2023, 7, 11], 'from': [2024, 5, 20], 'to': [2024, 7, 20]}, [366, 5200]), ('partial-repair probe', {'price': 36600, 'start': [2023, 4, 2], 'from': [2024, 2, 21], 'to': [2024, 5, 8]}, [366, 4100]), ('normal control', {'price': 36500, 'start': [2024, 8, 1], 'from': [2025, 7, 3], 'to': [2025, 8, 1]}, [365, 2900]), ('normal control', {'price': 119900, 'start': [2025, 2, 27], 'from': [2026, 3, 9], 'to': [2026, 3, 7]}, [365, 0]), ('normal control', {'price': 119900, 'start': [2025, 5, 10], 'from': [2025, 11, 11], 'to': [2025, 11, 9]}, [365, 0]), ('normal control', {'price': 36500, 'start': [2022, 7, 6], 'from': [2022, 6, 17], 'to': [2022, 7, 2]}, [365, 0])], [('regression', {'price': 36600, 'start': [2024, 1, 24], 'from': [2024, 4, 28], 'to': [2024, 5, 27]}, [366, 2900]), ('regression', {'price': 119900, 'start': [2025, 7, 19], 'from': [2025, 8, 25], 'to': [2026, 1, 13]}, [365, 46318]), ('partial-repair probe', {'price': 36500, 'start': [2024, 2, 29], 'from': [2025, 1, 6], 'to': [2025, 5, 17]}, [366, 5385]), ('partial-repair probe', {'price': 36500, 'start': [2024, 6, 2], 'from': [2025, 2, 2], 'to': [2025, 7, 10]}, [365, 12000]), ('normal control', {'price': 36500, 'start': [2023, 9, 5], 'from': [2024, 8, 17], 'to': [2024, 9, 5]}, [366, 1895]), ('normal control', {'price': 36500, 'start': [2025, 2, 5], 'from': [2025, 6, 6], 'to': [2025, 6, 1]}, [365, 0]), ('normal control', {'price': 108823, 'start': [2025, 11, 11], 'from': [2026, 6, 23], 'to': [2026, 6, 21]}, [365, 0]), ('normal control', {'price': 36600, 'start': [2025, 7, 27], 'from': [2026, 7, 12], 'to': [2026, 7, 11]}, [365, 0])], [('regression', {'price': 119900, 'start': [2025, 7, 19], 'from': [2025, 8, 25], 'to': [2026, 1, 13]}, [365, 46318]), ('regression', {'price': 975972, 'start': [2023, 4, 12], 'from': [2023, 10, 30], 'to': [2024, 1, 23]}, [366, 226660]), ('partial-repair probe', {'price': 36500, 'start': [2023, 5, 7], 'from': [2024, 4, 18], 'to': [2024, 10, 6]}, [366, 1895]), ('partial-repair probe', {'price': 835323, 'start': [2022, 3, 25], 'from': [2023, 1, 26], 'to': [2023, 6, 21]}, [365, 132736]), ('normal control', {'price': 971485, 'start': [2023, 1, 17], 'from': [2023, 3, 30], 'to': [2023, 3, 29]}, [365, 0]), ('normal control', {'price': 36500, 'start': [2025, 7, 17], 'from': [2025, 6, 28], 'to': [2025, 6, 28]}, [365, 0]), ('normal control', {'price': 119900, 'start': [2024, 12, 22], 'from': [2025, 11, 10], 'to': [2025, 11, 8]}, [365, 0]), ('normal control', {'price': 119900, 'start': [2024, 2, 26], 'from': [2025, 2, 15], 'to': [2025, 2, 12]}, [366, 0])], [('regression', {'price': 975972, 'start': [2023, 4, 12], 'from': [2023, 10, 30], 'to': [2024, 1, 23]}, [366, 226660]), ('regression', {'price': 36500, 'start': [2025, 4, 22], 'from': [2025, 10, 5], 'to': [2026, 2, 9]}, [365, 12700]), ('partial-repair probe', {'price': 36600, 'start': [2023, 1, 26], 'from': [2023, 10, 15], 'to': [2024, 3, 11]}, [365, 10328]), ('partial-repair probe', {'price': 36500, 'start': [2023, 12, 16], 'from': [2024, 10, 29], 'to': [2025, 3, 10]}, [366, 4787]), ('normal control', {'price': 119900, 'start': [2022, 6, 19], 'from': [2022, 10, 26], 'to': [2022, 10, 23]}, [365, 0]), ('normal control', {'price': 36500, 'start': [2024, 5, 30], 'from': [2025, 2, 16], 'to': [2025, 2, 12]}, [365, 0]), ('normal control', {'price': 100385, 'start': [2025, 10, 15], 'from': [2026, 10, 7], 'to': [2026, 10, 15]}, [365, 2200]), ('normal control', {'price': 36600, 'start': [2023, 12, 24], 'from': [2023, 12, 9], 'to': [2023, 12, 10]}, [366, 0])]]
for i, (label, args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (label, i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression 0	`[365, 33178]`	`[365, 33178]`	Passed
regression 1	`[365, 79526]`	`[365, 79526]`	Passed
partial-repair probe 2	`[366, 11600]`	`[366, 3800]`	Failed
partial-repair probe 3	`[365, 21995]`	`[365, 20896]`	Failed
normal control 4	`[365, 2200]`	`[365, 2200]`	Passed
normal control 5	`[366, 0]`	`[366, 0]`	Passed
normal control 6	`[366, 0]`	`[366, 0]`	Passed
normal control 7	`[365, 0]`	`[365, 0]`	Passed

SHA-256 / f08c1fb77c58cceceb8db66e1643e5c2d746459c67cf75cb9a41532eddba4dae

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import datetime
import calendar
N = 1
observations = []
def solve(x):
    s = datetime.date(*x['start'])
    try:
        e = s.replace(year=s.year + 1)
    except ValueError:
        e = datetime.date(s.year + 1, 3, 1)
    f = max(datetime.date(*x['from']), s)
    t = min(datetime.date(*x['to']), e)
    days = max(0, (t - f).days)
    total = (e - s).days
    return [total, (x['price'] * days * 2 + total) // (2 * total)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression', {'price': 119900, 'start': [2022, 1, 5], 'from': [2022, 2, 1], 'to': [2022, 5, 13]}, [365, 33178]), ('regression', {'price': 617594, 'start': [2024, 4, 7], 'from': [2024, 5, 22], 'to': [2024, 7, 8]}, [365, 79526]), ('partial-repair probe', {'price': 36600, 'start': [2023, 6, 28], 'from': [2024, 5, 21], 'to': [2024, 9, 14]}, [366, 3800]), ('partial-repair probe', {'price': 401416, 'start': [2025, 2, 14], 'from': [2026, 1, 26], 'to': [2026, 2, 15]}, [365, 20896]), ('normal control', {'price': 100385, 'start': [2025, 10, 15], 'from': [2026, 10, 7], 'to': [2026, 10, 15]}, [365, 2200]), ('normal control', {'price': 36600, 'start': [2023, 12, 24], 'from': [2023, 12, 9], 'to': [2023, 12, 10]}, [366, 0]), ('normal control', {'price': 400202, 'start': [2020, 2, 29], 'from': [2020, 2, 19], 'to': [2020, 2, 18]}, [366, 0]), ('normal control', {'price': 547591, 'start': [2022, 5, 7], 'from': [2022, 12, 9], 'to': [2022, 12, 7]}, [365, 0])], [('regression', {'price': 617594, 'start': [2024, 4, 7], 'from': [2024, 5, 22], 'to': [2024, 7, 8]}, [365, 79526]), ('regression', {'price': 36600, 'start': [2024, 1, 24], 'from': [2024, 4, 28], 'to': [2024, 5, 27]}, [366, 2900]), ('partial-repair probe', {'price': 36600, 'start': [2023, 7, 11], 'from': [2024, 5, 20], 'to': [2024, 7, 20]}, [366, 5200]), ('partial-repair probe', {'price': 36600, 'start': [2023, 4, 2], 'from': [2024, 2, 21], 'to': [2024, 5, 8]}, [366, 4100]), ('normal control', {'price': 36500, 'start': [2024, 8, 1], 'from': [2025, 7, 3], 'to': [2025, 8, 1]}, [365, 2900]), ('normal control', {'price': 119900, 'start': [2025, 2, 27], 'from': [2026, 3, 9], 'to': [2026, 3, 7]}, [365, 0]), ('normal control', {'price': 119900, 'start': [2025, 5, 10], 'from': [2025, 11, 11], 'to': [2025, 11, 9]}, [365, 0]), ('normal control', {'price': 36500, 'start': [2022, 7, 6], 'from': [2022, 6, 17], 'to': [2022, 7, 2]}, [365, 0])], [('regression', {'price': 36600, 'start': [2024, 1, 24], 'from': [2024, 4, 28], 'to': [2024, 5, 27]}, [366, 2900]), ('regression', {'price': 119900, 'start': [2025, 7, 19], 'from': [2025, 8, 25], 'to': [2026, 1, 13]}, [365, 46318]), ('partial-repair probe', {'price': 36500, 'start': [2024, 2, 29], 'from': [2025, 1, 6], 'to': [2025, 5, 17]}, [366, 5385]), ('partial-repair probe', {'price': 36500, 'start': [2024, 6, 2], 'from': [2025, 2, 2], 'to': [2025, 7, 10]}, [365, 12000]), ('normal control', {'price': 36500, 'start': [2023, 9, 5], 'from': [2024, 8, 17], 'to': [2024, 9, 5]}, [366, 1895]), ('normal control', {'price': 36500, 'start': [2025, 2, 5], 'from': [2025, 6, 6], 'to': [2025, 6, 1]}, [365, 0]), ('normal control', {'price': 108823, 'start': [2025, 11, 11], 'from': [2026, 6, 23], 'to': [2026, 6, 21]}, [365, 0]), ('normal control', {'price': 36600, 'start': [2025, 7, 27], 'from': [2026, 7, 12], 'to': [2026, 7, 11]}, [365, 0])], [('regression', {'price': 119900, 'start': [2025, 7, 19], 'from': [2025, 8, 25], 'to': [2026, 1, 13]}, [365, 46318]), ('regression', {'price': 975972, 'start': [2023, 4, 12], 'from': [2023, 10, 30], 'to': [2024, 1, 23]}, [366, 226660]), ('partial-repair probe', {'price': 36500, 'start': [2023, 5, 7], 'from': [2024, 4, 18], 'to': [2024, 10, 6]}, [366, 1895]), ('partial-repair probe', {'price': 835323, 'start': [2022, 3, 25], 'from': [2023, 1, 26], 'to': [2023, 6, 21]}, [365, 132736]), ('normal control', {'price': 971485, 'start': [2023, 1, 17], 'from': [2023, 3, 30], 'to': [2023, 3, 29]}, [365, 0]), ('normal control', {'price': 36500, 'start': [2025, 7, 17], 'from': [2025, 6, 28], 'to': [2025, 6, 28]}, [365, 0]), ('normal control', {'price': 119900, 'start': [2024, 12, 22], 'from': [2025, 11, 10], 'to': [2025, 11, 8]}, [365, 0]), ('normal control', {'price': 119900, 'start': [2024, 2, 26], 'from': [2025, 2, 15], 'to': [2025, 2, 12]}, [366, 0])], [('regression', {'price': 975972, 'start': [2023, 4, 12], 'from': [2023, 10, 30], 'to': [2024, 1, 23]}, [366, 226660]), ('regression', {'price': 36500, 'start': [2025, 4, 22], 'from': [2025, 10, 5], 'to': [2026, 2, 9]}, [365, 12700]), ('partial-repair probe', {'price': 36600, 'start': [2023, 1, 26], 'from': [2023, 10, 15], 'to': [2024, 3, 11]}, [365, 10328]), ('partial-repair probe', {'price': 36500, 'start': [2023, 12, 16], 'from': [2024, 10, 29], 'to': [2025, 3, 10]}, [366, 4787]), ('normal control', {'price': 119900, 'start': [2022, 6, 19], 'from': [2022, 10, 26], 'to': [2022, 10, 23]}, [365, 0]), ('normal control', {'price': 36500, 'start': [2024, 5, 30], 'from': [2025, 2, 16], 'to': [2025, 2, 12]}, [365, 0]), ('normal control', {'price': 100385, 'start': [2025, 10, 15], 'from': [2026, 10, 7], 'to': [2026, 10, 15]}, [365, 2200]), ('normal control', {'price': 36600, 'start': [2023, 12, 24], 'from': [2023, 12, 9], 'to': [2023, 12, 10]}, [366, 0])]]
for i, (label, args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (label, i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression 0	`[365, 33178]`	`[365, 33178]`	Passed
regression 1	`[365, 79526]`	`[365, 79526]`	Passed
partial-repair probe 2	`[366, 3800]`	`[366, 3800]`	Passed
partial-repair probe 3	`[365, 20896]`	`[365, 20896]`	Passed
normal control 4	`[365, 2200]`	`[365, 2200]`	Passed
normal control 5	`[366, 0]`	`[366, 0]`	Passed
normal control 6	`[366, 0]`	`[366, 0]`	Passed
normal control 7	`[365, 0]`	`[365, 0]`	Passed

SHA-256 / b886936474ab4410668b9afeefca9befaa1911dcacf7f20d31abdeefdf745d3a

Verification & scope

A deterministic teaching model of a stipulated billing rule. It makes no claim to reproduce any billing provider's exact behaviour and is not billing software. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:46:38.180618+00:00.

Case digest / ded539e671e67c0739c6977713fd4cd99a7839dd23d55b3df73380da46aa6650