The new form field calculation is great, but I immediately ran into a snag implementing it on a PO form. I wanted to include line item totals for each line based on Quantity and Unit price fields filled in earlier, and then a PO Total field that adds together all line item totals.

The line item totals worked great. But the PO total doesn't fill in until every single line is filled in. Most POs this customer store only fill in the first one or two lines, so I can't create a PO Total field that's visible on the form. If I could check a box that says "Assume Blank field = 0" in the calculation window, I could make a running PO Total field that starts at 0.00 and adds up as more line items are added.

I've included an image to make the problem clearer.