---
task_id: "4"
task_hash: "sha256:d571027295959410fd431fe86fc37d769aa15e71d4e14fcb4e5c624b8960c193"
next: "Wave W3 task 5: calculation persistence and policy version validation"
completed: "BigDecimal calculation engine with cumulative withholding and override validation"
evidence: "mvn -Dtest=SalaryCalculationEngineTest test: 6/6 passed"
review: ".superpowers/sdd/reviews/T4.md"
risk: "Tax anchor cases will be expanded in W4"
commit_start: "2d315f90e46982e9658da6483f46e2acbe21bcca"
commit_end: "4b42a624d7ec2bb5cac64bc13cd7d4d8eba91ee7"
created_at: "2026-09-20T08:29:09.537Z"
plan_hash: "sha256:77341d6e000ef1624d59d66b8b361c24e7ef8f1b5d065dd4d648a2a7537e72d5"
plan_revision: 1
---

# Checkpoint: 4

## Next
Wave W3 task 5: calculation persistence and policy version validation

## Completed
BigDecimal calculation engine with cumulative withholding and override validation

## Evidence
mvn -Dtest=SalaryCalculationEngineTest test: 6/6 passed

## Review
.superpowers/sdd/reviews/T4.md

## Risk
Tax anchor cases will be expanded in W4

## Commit Start
2d315f90e46982e9658da6483f46e2acbe21bcca

## Commit End
4b42a624d7ec2bb5cac64bc13cd7d4d8eba91ee7