"as I understand your approach, you'd start at the partners level,"

I was explaining why numbers don't need to exactly match. Until USA follows Canada in eliminating pennies, you have a number you verified just fine.

"So don't I have to come up with the correct amounts at the partnership level before I allocate among the partners?"

Isn't that what you bought the software to do for you? There is a rule: Close enough. I was pointing out why even that form might not agree among itself.