First of all this library has been so useful. It's exactly what I needed and works really well. There is only one issue.
It seems to be detecting changes that aren't occurring. At first I thought the model was adding zeros or the db was removing them. But after some digging I think it's a bug with django-auditlog.
It thinks a change occurred anytime I save this record: it thinks that I started with .00 and changed it to .0. But .00 is the existing value and I didn't change anything. I just saved() the record.

I checked the output of the form itself in the clean() method:

services_sub_total
44.00
sum_payments
33.00

And then in the database:

I just cant figure out where/why this is detecting only one zero in the decimal place - I'm not seeing that .0 anywhere.
Could the delta functions be truncating multiple zeros in the decimals to .0?