Mortgage amortization not working

[Donald Allen]

It looks like Beth Leonard and I have run into the same problem. She
reports similar behavior to what I am seeing in her
"SXs for mortgage druid not paying attention to 'i' value" message. I
will post a copy of my message to her thread, to consolidate the two.

/Don Allen

On Wed, Feb 10, 2010 at 8:33 AM, Donald Allen <donaldcallen at gmail.com> wrote:
> I am running Gnucash 2.2.9 on an up-to-date Arch Linux system. The
> payment of my home mortgage is entered into Gnucash by a scheduled
> transaction. The problem is that the scheduled transaction does not do
> the mortgage amortization correctly, though that is what I intended
> when I set it up and it did work for awhile.
>
> I refinanced my mortgage on 5/1/2004, a 10-year fixed-rate mortage at 4.625%.
>
> The Overview tab of the scheduled transaction shows the Enabled and
> Create automatically boxes checked. In the Occurrences section, the
> Until radio button is selected, with the date set to 5/1/2014.
>
> The Frequency tab has the frequency set to Monthly, start date =
> 5/1/2004, every = 1 months, on the 1st.
>
> The template transaction looks like this (I’ve substituted x for the
> original amount of the mortgage for privacy reasons):
>
> Description                                                             Tot debit       Tot credit
> Mortgage payment - Payment      Assets:Checking         n                       pmt( 0.04625 / 12 :
> 120.00 : x : 0 : 0 )
> Mortgage payment - Principal    Liabilities:Mortgage            n       ppmt( 0.04625 /
> 12 : i : 120.00 : x : 0 : 0 )
> Mortgage payment - Interest     Expenses:House:Mortgage int.    n       ipmt(
> 0.04625 / 12 : i : 120.00 : x : 0 : 0 )
>
> (Apologies for the alignment, if it doesn't look right. Tabs are a
> problem in Gmail. The formula for the payment is in the Tot credit
> column, those for the Principal and Interest are in the Tot debit
> column.)
>
> What is happening is that every month, I get an automatically
> generated transaction where the principal and interest payments are
> those that would be correct if the payment were dated 3/1/2008. So I’m
> getting this constant 3/1/2008 payment every month and every month I
> go in and fix it, having calculated the correct amortization
> separately.
>
> This would appear to be a bug, though it’s certainly possible I’m
> doing something wrong.
>
> Ideas?
>
> /Don Allen
>