If you have pricing that is at 3 or more decimal places you need to have rounding setup in the Currency Master. There is also some confusion about where the total rounding is applied. It says sales, but is also used for AP.
Example 815 FT at .635 per foot is 517.525, but the invoice is for 517.30 so the Read invoice Integration returns a variance of .005 that has no way to ever be resolved from ECM.
Without rounding AP Invoice entry it is a pain, but in AP automation it is a workflow stopper.