2026-05-04-billing-tax-recompute

Long-termPreserved permanentlybilling-sampleMay 1, 2022, 4:12 PM

Post-log (TL;DR)

Passed 3–0, drifted on a bad source-table entry, reconsidered unanimously,

# Post-log — Billing committee, monthly tax recompute

**TL;DR:** Passed 3–0, drifted on a bad source-table entry, reconsidered unanimously,
amended with a sanity check, re-passed 3–0.

## Key decisions

- Monthly recompute against source-of-truth tax table.
- Credit memo + re-invoice in a single transparent message.
- **Amendment:** per-jurisdiction outlier detection (anything > 3σ from neighbors flagged
  before recompute fires).

## Outcome

- Original shipped 2026-05-08. Caught a 0.5pp error in an Alabama county source entry.
- Reconsideration filed 2026-05-12 by Bob, motion unanimous.
- Amended version shipped 2026-05-15. Zero drift observed in 14 days.

## Next actions

- Continue to monitor source-table accuracy at month-end.
- Sample-evaluator scoring window ends 2026-06-15.

Full transcript

# Full transcript — Billing committee, monthly tax recompute

**Date:** 2026-05-04
**Attendees:** Alice, Bob, Carol, Dana (observing)

---

**Alice:** Three jurisdictions changed sales tax in Q1. Two we caught at month-end after
invoices had already gone out. That's brand damage.

**Bob:** What's the proposal?

**Alice:** Monthly recompute against the source-of-truth table. On the 1st, sweep
everything, issue credit memos for any drift, re-invoice transparently.

**Carol:** Customer comms look clean. Single message, not a series.

**Bob:** I approve, but I'm flagging that the source table itself is the weak link. If
their data is wrong, ours is wrong with confidence.

**Alice:** I think that's a second proposal.

**Bob:** I'll file a reconsideration if I see drift.

**Alice:** Fair. Vote?

**Bob:** Yea.
**Carol:** Yea.
**Alice:** Yea.

---

**Outcome (original):** Passed 3–0. Shipped 2026-05-08.

---

## Reconsideration — 2026-05-12

**Bob:** As predicted. Alabama county source entry was wrong by 0.5pp. Fourteen invoices
went out at the bad rate before we caught it. The recompute amplified the error instead
of catching it.

**Alice:** What's your motion?

**Bob:** Per-jurisdiction sanity check. Anything > 3σ from neighbors gets flagged before
the recompute fires.

**Carol:** Approve the motion to reopen.

**Alice:** Approve. Unanimous?

**Bob:** Unanimous.
**Carol:** Unanimous.
**Alice:** Unanimous. Motion carries.

**Amended proposal:** Original + per-jurisdiction outlier detection.

**Alice:** Yea.
**Bob:** Yea.
**Carol:** Yea.

**Outcome (amended):** Re-passed 3–0. Shipped 2026-05-15. No further drift in 14 days.