<Detail Loop Count> keyword in lieu of CTT 1.0

The Analysis: You are right, creating a work field and counting the PO1 segments will do the trick. But this is tedious. The software has a keyword called <Detail Loop Count> which contains the running count of the document details. The document detail segment is decided or configured in the Format Properties-Control Totals tab.

The Solution: Pick a segment that is surely past the Details portion of the document (for this PO1 Loop) and map the keyword <Detail Loop Count> to the field where the CTT 1.0 used to be mapped.