I have been working with the ecommerce module for some weeks, and i think i have cleaned the bugs you are pointing, along with some more. I have been using it for some time without errors (but i'm afraid i haven't tested it deeply yet, so maybe there are still some uncaught bugs).
Let me work a couple of days in my local cvs (mostly to get rid of some junk i may have included in the code), and i will post a .diff.
I have a question, though. Should i make my diff against the newest cvs version, or against official 3.2.4 version? I think the last option is better, because you if you have the 3.2.4 version you'll be completely sure than the patch will work without complaints.
What does people think about it?