@ThereseLogeais beat me to it.........
Also, on the data tab, you may have to include the credit and debit fields as the first lines so that your test logic precludes creating the header data. It's not that the record is importing zeros, it's just creating the header, your logic kicks in after the fact and is working so the line info doesn't get imported. As a result, but the default is zero since it can't be blank.
Or calculate a temp field and make it the first line on the data tab and set your logic test to check that value first.
I would try the skip record, though. You'll need two lines on that tab, I believe.
I haven't tested any of it.............