...
Aspenware has introduced an optional MatchTaxCalculation setting to ensure that when there is a tax discrepancy between Nopcommerce (what the customer paid in tax) and what RTP recalculates as the tax amount, the order placed into RTP via Unity always matches RTP’s method of tax allocation so that this reconciliation overhead is alleviated. This setting does not make Nopcommerce tax and RTP tax calculation match, so while this setting change it can alleviate issues with onsite order discrepancies, accounting , and other groups will need to be alerted to and agree to of the fact that NOP and RTP will be out of balance slightly if this new setting is set to true.
...
When the MatchTaxCalculation setting is set to 'TRUE,' tax calculations in Unity will align with RTP calculations, . RTP uses bankers rounding in most cases (see “Add a Penny Logic” exceptions below). This ensures a $0 balance when comparing orders in Unity and tax calculations in RTP.
Please note that this might result in a difference between the deposit in RTP and what the user was charged in nopCommerce due to tax differences between the two systems. RTP uses bankers rounding and applies custom logic for rounding when necessary (see “Add a Penny” below).
...