Financial HP Calculator: Amortisation with Payments at begin of period

[Gil]

Thanks, Werner, for your reply.

I saw that unexpected — but understandable — issue when checking the given results by the HP50G with my own complete TVM-Growth-Amortisation program that includes the possibility of C/Yr ≠ P/R and Payment-Growth≠0.

By the way, how do handle your different calculators models the case of rounding each intermediate result to the cent (2 RND)?

The HP50G, with its own built-in program, looks if 2 (3, 4, etc.) FIX was set and then execute "2 RND".

As far as I am concerned, when amortising at the very beginning for the first time, I decided to allocate, on stack level 2, once a value of 1 (for rounding) or 0 (exact, no rounding) to a variable called rd just before entering, on level 1, the wished number of payments to be amortised the first time; then, the 2nd group, the 3rd group, etc. of amortising payments don't require the above setting on level 2, but just on level 1 the required new payments to be amortised.

Then, for each intermediary result — new p, new int — , if variable rd = 1, then the program executes 2 RND.

The option would be not to test anything,
but executing the 2 commands in a row —>STR OBJ—>,
having set previously (or not for no rounding) the mode 2 FIX to see the rounding effects.

I don't know which solution is the most appropriate: the latter one from the built-in convention calculator program, or the one obliging you to enter once, in level 2, if rounded results are wished or not.

Commentaries about the above welcome.

Regards,
Gil