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05-07-2017 09:42 PM - edited 05-07-2017 09:46 PM
I have a HP 12C Gold, and I'm getting a strange behavior when using the amort key.
For example, if I set payment mode to end (g END) and calculate a uniform serie compound with n=10 (10 n), i=10 (10 i), PV=10000 (10000 PV) and ask for PMT (PMT), I got about -1627.45 for each payment.
So, if I amort one period (1 f AMORT) to create a price amort table, the registers in the screen are X=-1000.00 (amortized value) and Y=-627.45 (interest payment). And if I ask the calculator the remaining PV (RCL PV), I got 9372.54. Evething seems ok.
And now I ask the calculator the financial registers, i=10 (RCL i), PMT=-1627.45 (RCL PMT) and FV=0 (RCL FV). However, when I ask n, I got n=11 (RCL n), but I expected to get n=9 because now there are nine periods to pay the remaining amout of PV=9372.54.
I think n=9 should be the expected value in the n register, because the new situation is equivalent a new uniform serie compound with PV=9372.54, i=10, FV=0 and n=9 (that would return the same PMT=-1627.45). Setting n=11 seems like a bug or an inconsistent value.
So, why n=11 (incremented by one) instead of n=9 (decremented by one and consistend with the remaining debt)?
Solved! Go to Solution.
05-08-2017 06:28 AM - edited 05-08-2017 04:26 PM
Have a nice day !.
@Maké (Technical Advisor Premium - HP Program Top Contributor).
Provost in HP Spanish Public Forum ... https://h30467.www3.hp.com/
05-08-2017 04:01 PM
On the HP-12C you should not run the TVM before doing AMORT. See p54 of the PDF manual:
If you do run the TVM (e.g. to calculate PMT), then n must be set to 0 before doing AMORT
See p56 of the PDF manual:
If you want to generate an amortization schedule but do not already know the monthly payment:
1. Calculate PMT as described on page 46.
2. Press 0 n to reset n to zero.
3. Proceed with the amortization procedure listed on page 54 beginning with step 6.
It seems the 12C adds to n when the AMORT is used. e.g. if you don't reset n and look at the 10th period (10 f AMORT) then RCL n it will be 20.
So whenever you have calculated any TVM, first set n to 0 before doing AMORT.
05-08-2017 08:59 PM
Thank you for the response!!! It was a very good and clear explanation!
Adding more info... From the p54 of the PDF manual:
>To display the total number of payments amortized, press (RCL n).
So, when doing amort, n is the total of amortized periods, and NOT the number of remaining periods to amortize.
Again, thanks for the explanation!
05-08-2017 09:04 PM
Thanks for the response. The link https://support.hp.com/rs-en/document/c01855972, for example, was very good and clear!
From the link:
> [...] every time [f] [AMORT] is pressed, the following registers have their contents updated:
> [n] Contents updated to current number of payments amortized.