FAQ: Why do 2 identical invoice lines have different tax amounts?

To calculate transaction tax amounts on a taxable document, Workday first calculates these amounts at the tax rate application (TRA) level:

TRA	Calculation
Taxable Amount	The sum of the extended amounts on the lines that share the TRA attributes.
Transaction Tax Amount	Tax rate × TRA taxable amount
Recoverable Tax Amount	Recoverability percentage × TRA transaction tax amount

Workday rounds these amounts based on the rounding definition of your tax authority.

Then, Workday distributes the tax amounts to the lines on the taxable document and rounds them.

To balance the sum of the line tax amounts with the TRA tax amounts, Workday adjusts the line with the greatest extended amount. When several lines have the same extended amount, Workday adjusts only the line with the lowest line ID. As a result, 2 identical lines might have different transaction tax amounts.

Workday applies the same calculation and rounding to withholding taxes.

Example: You want to calculate transaction tax amounts on a supplier invoice with these lines:

Line ID	Extended Amount (USD)	Tax Rate (%)
1	100.05	8
2	100.05	8
3	100.05	8
4	100.05	8

On all these lines, you enter the same tax:

Applicability

Code

Option

Rate

Recoverability

You also configure the tax authority to round tax amounts to the nearest 2 decimal places.

Since these lines share the same tax attributes, Workday creates 1 TRA:

TRA	Calculation	Total
Taxable Amount	100.05 × 4	400.20
Tax Amount	8% × 400.20	32.016 (rounded to 32.02)

Workday then:

Distributes the TRA transaction tax amount to the 4 lines: 32.02 ÷ 4 = 8.005, rounded to 8.01, for a total of 32.04.

Adjusts the transaction tax amount of line 1 to 7.99 to balance the line and TRA totals to 32.02.

As a result, the transaction tax amount of line 1 differs from the other lines:

Line ID	Extended Amount (USD)	Tax Rate (%)	Tax Amount (USD)
1	100.05	8	7.99
2	100.05	8	8.01
3	100.05	8	8.01
4	100.05	8	8.01