I also was
unable to ever get the bank to tell me exactly how
interest was calculated - I had to juggle possibilities myself until
I came up with one that tracked the bank's numbers exactly.
Well, it was
sitting on PC's as an open source basic program for
years. 'mortgage.bas', IIRC. Personal belief is that all interest
rate calculations operate like this, with the banks options only
being what to do when a person wants to prepay, and, optional fees at
closing.
I couldn't say without knowing what mortgage.bas did. I do suspect,
though, that it would be designed for US mortgages and thus at least
somewhat inapplicable to mine, which was Canadian. (In case anyone
cares: they de-compounded the quoted rate to a daily rate, with
different rates in leap and non-leap years, and then charged interest
at that daily rate, with payments wherever they fell.)
Certainly when I asked on mortgage-ca, nobody seemed to know.
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