Should Price Override Code (PROV) be a 1 in the F4311 on a J line type

We had a situation where a user changed the quantity on a PO and the unit cost and extended amount went to zero.  I checked the F4311 and found the PROV (price override code) was blank for this line.  The line was a J line type so the unit price was manually entered when the PO was created.  I looked at other lines on the order (all J line types) and found some lines at the PROV equal to blank and other it was equal to a 1.  The lines where the PROV was equal to 1 when the quantity