I think I am doing this the wrong way.

I send an estimate that gets accepted.i usually create an invoice when I get the

P.O #. When order us ready I print the p/slip and send invoice.

On the big orders I have been doing the same thing. But when I have 30 lines on the invoice and I ship 5 lines at a time, and do not invoice until all 30 lines have been shipped. This is when the p/slips become a pain. Perhaps I should not create the invoice from Estimate. 

Chris