Financial HP Calculator: Amortisation with Payments at begin of period

[Gil]

Do you really mean
PMT-1 = RND(PMT;2) = 2511.73
PMT-2 = RND(PMT*1.05;2) = 2637.32
PMT-3 = RND(PMT*1.05^2;2) = 2769.19

or rather

PMT-1 = RND(PMT;2) = 2511.73
PMT-2 = RND(PMT-1*1.05;2) = 2637.32
PMT-3 = RND(PMT-1*1.05^2;2) = 2769.19,
having the initial payment PMT-1 as reference for successive growth?

Depending on your confirmation or not I might change my program calculation for the successive PMT-i.

For the PMT-11, we might
have then "my" 4091.34350092 —>. 34
instead of your 4091.34983732 —>. 35, ie a cent of difference...

Interesting would be to know the most general banking use in that matter, though, of course, the difference is quite ridiculous here.

Regards,
Gil