Interest Loans have a duration in their contract draft set up
annuity and stable loans do not
for my purposes I will have duration = N, interest rate = r, repayment rate = R, principle = P, and payment = PMT.
To calculate the repayment rate for a stable loan it is R = 1 / N. P * R then gives the amount of the principle that is paid each week. As such I think it would be more intuitive for players to put in duration, N, rather than a repayment rate.
For an annuity loan every payment, (interest and principle) is the same every week. To this end the phrase “initial repayment rate” is ambiguous and unhelpful. As best as I can tell it is R = r / (-1 + (1 + r)^N). To calculate real annuity loans’ payment it is, PMT = P * r / (1 - (1 + r)^-N)
So for example, for 1,000,000 AIC at 3% for 8 weeks would give a payment of 142,456.39, and in game you would see a payment of 142,456 for 4 of the 8 weeks and 142,455 for the other 4 weeks. They are not actually level payments in the game they are almost level payments.
To solve this and respect the how I think the game deals with decimals in contracts, I suggest rounding the PMT down to the nearest whole number or maybe even half number. IE 142,456.39 to 142,456.
I think this would make in game contract loans more friendly.
Best,
Hal98 | Friendly Metals