It seems that Project Accounting has its own tax engine - separate and apart from the Microsoft Dynamics GP tax engine. The Project Accounting tax engine does not properly handle certain tax details. Case in point are counties in Florida that have a maximum amount taxable of $5,000.

1. Project Accounting seems to ignore the maximum amount taxable, however it does respect a maximum tax amount.
2. Project Accounting fails to handle the above referenced range and maximum tax amount unless the setup window field “Include” (range type) is set to “Full amount” as opposed to the normal setting of “Amount within Range”.
3. The Microsoft Dynamics GP tax engine will restrict the tax charged to the Max Tax amount for the entire document rather than per unit or per extended price. This means in effect that “fixing” the problem for Project Accounting can “cause” a problem for the rest of Microsoft Dynamics GP.

Known Microsoft Dynamics GP Issues