loan/mortgage repayment via sched xactions: feedback request

[Ross Boylan]

I just reviewed this thread and have a couple of belated comments.

1. For variable rate mortgages there are potentially lots of dates
involved in the reseting:
date the user gets the notice of the new rate
date the user enters the new rate
date the new rate takes effect

I think these could occur in any order, given that people may not pay
attention (so new rate takes effect before they enter it) or could be
figuring the rate out in advance.  It's easy to imagine someone not
realizing the rate had changed and sending out the old amount and
entering it in gnucash.  Of course, the typical user of gnucash is
probably less likely to make such a mistake than the typical person :)

The key point is that a model where someone just enters the new rate
and then it takes effect is probably inadequate.

2. I want to underline the comments that it may be hard to know what
happens to overpayments or advance payments, and that subsequent
calculations will depend on the answers.  I don't see how computing
the dollar amount of all the quantities in advance can work, since
someone can make an extra payment (or lapse payments) at any time.
I'm not entirely clear if such advance calculation was being proposed.

As another example, my bank sent me a note urging me to make 2
payments a month to accelerate my repayment.  Also, there is another
payment type: they have a penalty if you miss a payment.

There are at least two issues here: handling of unscheduled payments,
and whether computations can be done up front.

3. I've found that the amounts calculated by formula (in Managing Your
Money) do not quite match those the bank gets.  The difference was
small, and it may be simplest just to ignore the issue.  Also, the
final payment is a little different, reflecting the fact that exactly
equal payments don't quite work.  I don't know if the routines you are
contemplating capture this, and again it's a small amount.

4. I hope there will be both a rich low-level model and a way of
concealing most of it from most users.

5. Maybe a refinancing Druid would be good for version 10.  I don't
mean a "should I refinance wizard" (good too), but a "I just
refinanced this mortgage and need to take care of retiring the old
loan and entering the new one."

By the way, congratulations to all for some fine analysis of a tough
problem.