GHAMOD findings ledger — GH_2025 full-surface validation (12 entries)

[MaxGhenis]

This is the outward-facing ledger of divergences we observed between GHAMOD (SOUTHMOD Ghana, bundle A4.0, system GH_2025, dataset gh_2017_a8) and the governing Ghanaian instruments, found while building statutorily-grounded encodings of the full GH_2025 policy surface and validating them case-by-case against GHAMOD as the household-level oracle. Every encoded amount comes verbatim from captured official prints; every divergence below was observed live and is dispositioned in the oracle suite that covers it.

Model findings (12 entries; four are defect candidates, the rest are documented simplifications):

1. tin_s applies five marginal bands and taxes chargeable income above 238,760 GHS at a flat 30%, never applying the Act 1111 35% top rate above 605,000 GHS (probed: 193,244 vs statutory 197,994 at 700,000 chargeable).
2. The Act 896 Fifth Schedule ¶1(f) training relief (tinta04) is not modelled — the relief is inactive and produces no output column.
3. The Fifth Schedule ¶1(a) lone-parent limb (tinta02) never fires for lone parents with two dependent children.
4. SSNIT contributions (tscee/tscer) apply an age-15–45 contributor cap not present in Act 766.
5. tiniy taxes informal incomes at a 15% rate unsupported by First Schedule ¶8.
6. The turnover-tax eligibility band (10k–120k) reflects a superseded threshold.
7. The VAT wedge double- and triple-counts the levies: effective 27%/33% versus the statutory 21.9% composite.
8. Fuel levies omit the Road Fund and Energy Fund levies and miswire the petrol Sanitation and Pollution Levy.
9. LEAP pays bi-monthly amounts monthly (a 2× overstatement).
10. Free SHS amounts have no official documentary basis.
11. Excise buckets diverge from the Act 1108 table on several commodity groups.
12. tin taxes gross employment income, omitting the Act 896 s.112(2) deduction of the employee SSNIT contribution from the tax base.

Canonical artifacts

• Program tracker with the full narrative ledger: GHAMOD full-surface parity program #10
• Machine-readable entries with probed values: axiom_oracles/data/ghamod_issues.json (on the oracle review chain)
• Per-suite dispositions: the comparisons/gh-*.yaml configs in axiom-oracles

Scope and discipline. The SOUTHMOD bundle is licensed and non-redistributable: nothing here reproduces bundle content — only comparison statistics and values GHAMOD itself produced. Findings are stated against the captured official prints (Parliament of Ghana / Ghana Publishing Company), which are cited in the encodings. Corrections and context from the GHAMOD/SOUTHMOD team are very welcome in this thread.