FA-62618 / Tax bracket computation / Member archive

Only the larger surcharge applies to a non-resident additional dwelling · case 03

Non-resident second-home buyers pay 3 surcharge points instead of 5.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

solve(price, ftb, additional, nonresident): stipulated property transfer tax in whole pounds. Normal slices: 0% to 250000, 5% to 925000, 10% to 1500000, 12% above. First-time-buyer slices (0% to 425000, 5% to 625000) apply only when ftb is true, the purchase is not an additional dwelling, and price <= 625000; otherwise normal slices. Surcharges add percentage points to every slice including 0% slices: +3 for an additional dwelling when price >= 40000, +2 for a non-resident buyer; they stack. Return the tax rounded down to whole pounds.

Why this case matters

Tax computations hinge on which slice, threshold, ordering and rounding rule applies at each step; a misplaced boundary silently misstates liabilities.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression surcharge-stacking 1	`37500`	`50000`	Failed

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