can i set a body field (e.g. "customer" on a PO) based on a field on the item record (for example, the "customer" value on the first line item's item record) via workflow?

i'm not sure, my thought to try it would be to grab said customer value from the first item using line 1 logic to target only that line (or 0 depending on how NS set it up, but I'd think 1) and set that in a WF or State field and then use that value to set the value of customer on the PO. Not sure if you can set items before the customer via WF though, I would think so but haven't ever done it. Perhaps you could skip that hassle and just kind of 'source it' using the same logic, so straight from the first line to the customer field.

was thinking that too - ultimately though i've got a script already running on create of the transaction so i'm probably just going to go ahead and add it in there

np, makes sense

honestly that was in the back of my mind too, though i thought i would try setting it on before submit, and ideally any scripts (like an approval script) would run on after submit. but still, better to handle it in the same spot