Support sub-cent unit price precision on one-off invoice line items
Lago admin
On one-off invoices, the unit price is limited to 2 decimal places because it's stored/entered as whole cents (unit_amount_cents, integer). Line total is computed as unit_amount_cents × units, rounded. For partial-period / prorated charges, the true per-unit price is often fractional (e.g. $0.1467/unit), so we can't produce a line that hits the exact total while keeping the unit price honest.
Current workarounds that are incomplete:
- Decimal units (e.g. 102.3 units) — hits the exact total, but they read "units sold" off the invoice into their internal reporting, so fractional units corrupt the numbers.
- Second "proration adjustment" line to carry the remainder. This produces the exact total with clean integer units, but looks weird to end customers.