What formula does Manager use to calculate interest?

So I tried using Manager to calculate interest. But the formula that it uses seems to be different than the one I use because I’m getting different values. Can anyone tell me the formula that Manager uses to calculate interest? Thanks!

What do you mean by interest? Are you referring to late fees? If so, this is not an interest calculation. It is triggered by the due date but is not time-dependent. Manager has no formula for calculating interest.