## TL;DR
A half-cent unit difference usually comes from pack pricing: the PO prices per unit from a pack price divided by pack quantity, and the invoice rounds that division differently. Multiply both prices by the line quantity and compare extended amounts; if the extended difference is a few cents, approve it as rounding and record the reason. Then fix the source: store the unit price at higher precision or set the tolerance floor in currency so sub-cent unit noise stops blocking invoices.

```text
PO unit price differs from invoice by $0.005: "tolerance exceeded" error blocks approval
```

## Use this when
- Unit prices differ by a fraction of a cent, here 0.005, and tolerance exceeded fires.
- The item is bought in packs, cases, or bulk units converted to eaches.
- The extended line difference is only a few cents.

## Not for this skill when
- The unit difference is small but the quantity is huge, making the extended difference material. Treat it as a real price variance.
- The invoice price is a deliberate increase dressed as rounding across many lines. Compare total invoice impact before approving.

## Steps
1. Compute the extended amounts at PO price and invoice price for the actual line quantity. Verify: the extended difference is stated and is only a few cents
2. Rebuild the unit price from the pack or case price and its conversion to see which side rounded. Verify: the 0.005 is reproduced by the division arithmetic
3. Check the tolerance configuration: whether it is percent only, currency only, or both, and which one fired. Verify: you know the exact rule that blocked the invoice
4. Approve the variance with the rounding explanation recorded, if the extended difference is within your currency threshold. Verify: the approval note shows the extended difference, not just the unit difference
5. Fix the recurrence: raise stored price precision or add a minimum currency tolerance for low-price items. Verify: a test invoice with the same pack price matches without intervention

## Variant phrasings
### unit price difference half cent tolerance exceeded
The sub-cent phrasing.
### PO price rounding pack size invoice mismatch
When pack conversion is the cause.

Compatibility: Price tolerance configuration in SAP, Oracle, NetSuite, and Dynamics AP matching for low unit price items.

## Why it happens
Unit prices for cheap items live below the cent: a case price divided by units per case rarely lands on a clean cent. Each system rounds that division at a different precision, so PO and invoice disagree by design while agreeing on the only number that matters, the extended total. Percent tolerances make it worse because half a cent on a four-cent item is a double-digit percent variance.

## Edge cases / pitfalls
- Summing many approved rounding variances across a year can still be visible. Track them in aggregate per vendor.
- If both systems can store five-decimal unit prices, align precision there rather than widening tolerance.
- Watch for quantity games: a vendor billing more units at a slightly lower price can hide inside rounding approvals. Extended totals catch it.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_SZrSfIpRqlMKt2DDPlSuTQ