ArticlesPSA: Why Is There a Variation in Decimal Amounts During The Invoicing Process?

• Difference in the decimal amounts of Project Billings, Billing Event generation Preview, Billing Event and Billing Event
• On Project when trying to Generate Billing Events, with all Eligible Billing Records Included, for the Tiemcard Splits, the Total Billable amount shows more than the Net Total amount by few cents

• Professional Services Automation
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• The Variation seen in the Decimal Amounts, typically involves small cent differences, is a classic rounding discrepancy caused by the way PSA handles high-precision calculations across different record levels
• PSA performs calculations at the Timecard Split level using more than two decimal places, but then rounds to two decimals at the Billing Event and Sales Invoice levels
  • Timecard Split Level: PSA calculates the billable amount for each individual split (e.g., Hours * Bill Rate). If your bill rate or hours have multiple decimals, the resulting amount often carries 4+ decimal places (e.g., EUR 100.1234)
  • Billing Event / Sales Invoice Level: When these splits are grouped into a Billing Event, PSA typically sums the rounded two-decimal values of each item rather than summing the raw, high-precision values first
  • The Result: A "sum of rounds" often differs from a "round of sums." Across thousands of splits, these fractions of a cent (EUR 0.001) accumulate into the EUR 0.08 difference can be seen

• This is classic rounding discrepancy caused by the way PSA handles high-precision calculations

Billing Event & Sales Invoice Logic

• Billing Event Generation:
  • During the Preview Screen, PSA pulls all eligible Timecard Splits
  • The preview usually displays the sum of the Billable Amount field from those splits
  • If any individual split has been manually adjusted or if a rounding rule is triggered at the header level (e.g., group discounts or taxes), the total will shift.
• Sales Invoice:
  • The Sales Invoice is the final legal document and often uses a different rounding engine (like the one in your ERP/Accounting system)
  • It may apply Tax or Header-level adjustments that re-calculate the total based on the invoice's own precision settings, potentially causing another slight shift from the PSA Billing Event
• The "Billings" KPI Rollup
  The Billings KPI on the Project record is a rollup of all "Released" Billing Events.
  • Rollup Source: It typically pulls from the Amount field on the Billing Event (or Total Price on Billing Event Items)
  • Timing: This value only updates once the Billing Event is Released. If you generate a draft Billing Event but don't release it, the KPI won't reflect the new amount
  • Variance: Because this KPI is a rollup of already-rounded Billing Event totals, it will match the Billing Event total exactly but may still differ from the sum of the original "raw" Timecard Split data