The Line Item Detail - Percent Profit field is not labeled, is located directly to the right of the Cost field, and displays the gross profit for the line item represented as a percentage of the Price.
The following formula is used to calculate Percent Profit:
Percent Profit = ((Price - Cost)/Price)*100
Editing the Percent Profit on the Line Item Detail screen changes the Price and Total w/ Tax fields, but does not adjust Cost. It does not change the Percent Profit field in the item's Inventory database record.
See:
Line Item Detail Screen Contents
Sales Manager Contents