No Error for Taxable amount not equal to Gross amount if Tax is ZERO

Hi,

User has entered invoice (Standard AR Entry) with Tax rate as 0% and explanation code as V... The Gross Amount entered is 1000$ and Taxable amount as $900, tax amount is ZERO still there is no error on saving the record and even if we edit and change the taxable amount to 800, 700... there is no error.

In F03B11 and F0018 it is showing $100 as non-taxable and taxable as $900..

I checked the setup in P0022 it is setup to give an error if change is more than 10% and warning at 2% but it will not work as the Tax it always ZERO.

Questions: