HP 10BII+ C/Y Equivalent function

[yuyu12]

I can't find the equivalent of the C/Y function on the HP BII+. I found this answer: https://h30434.www3.hp.com/t5/Tablets-and-Mobile-Devices-Archive-Read-Only/Re-What-is-the-C-Y-equiva...

But the link it provided doesn't work and I don't think the 2nd link answers my question. My question would be similar to what was asked there:

"The Turgott family have just bought a house that they financed with a mortgage. They borrowed $80,000 at 11.5% and amortized the mortgage over 25 years, with a 5-year term.

a. What are their monthly mortgage payments?

(Set C/Y to 2 and P/Y to 12)

-80,000 PV

300 N

11.5 I

PMT = 797.65

I get 813.18"

Because there's no C/Y function on the HPBII+ (at least from what I can see), I'm not sure if there's another equivalent function that I can use.