TVM and example in User Guide

[salvomic]

hi,
with the example of page 292 in User Guide, I'm calculating the Amortization, but I get something different from that example (next page).
i.e.
I get (now with FW 7820):
P Principal Interest Balance
1 -1676.57 -9700.63 148323.43
2 -1788.85 -9588.35 146534.58
...
The example has:
P Principal Interest Balance
1 -1676.57 -9700.63 148323.43
2 -3465.42 -19288.98 146534.58

Is it a different mod of calc for amortization? or the values for TVM were different from those printed?

I would like to know more about the guidelines in Finance App...

Thank you,
Salvo

[kharpster]

Salvo,

You are correct sir, I did the same exercise as you and it looks like a group's principal and interest amounts are now only for a given group. Whereas in the previous firmware (verified with my Android emulator), they were accumulative amounts. An argument can be made to display it either way, but, I think it would be best to have the option to display it both ways with maybe a checkbox to select the desired format...

[salvomic]

(05-16-2015 10:43 PM)kharpster Wrote:  Salvo,

You are correct sir, I did the same exercise as you and it looks like a group's principal and interest amounts are now only for a given group. Whereas in the previous firmware (verified with my Android emulator), they were accumulative amounts. An argument can be made to display it either way, but, I think it would be best to have the option to display it both ways with maybe a checkbox to select the desired format...

hi,
yes, I think they now have uniformed the method of calc to that in the HP 12C.
In 12C I get result like mine giving i/12=6.5, n=0, PV=150000, FV=0, PMT=-948.10, with minus sign (important) (this can be solved in the Prime, or calculating by 12C putting n*12=30, that's n=360); then using 12, f+Amort I get the value for interest, with x<>y that for principal, with RCT PV the residual amount, and so on giving again 12 f+Amort...
So the result now is equal to that in the 12C, giving 12 as 12 is an year (12 months)...

Yes, I think that, a part of the choose for Group Size, it would be interesting to have also a choose for grouped or accumulative list...

I would like much to have also a complete Cash Flow routine in the Prime, like that in the 12C, I hope to test a program.
For now there is NPV (from Eddie Shore), that calculates Net Present Value; it would be nice to add also an IRR (Internal Rate of Return) function to it...

Salvo