Trying to look at the PB day question from all sides. More often than not, a weekend GS sums a couple of PB days mid week which mostly works to reset the 30 in 168 clock. If paid like a reg GS would it serve to push the 30 hour rest on a reserve day ….
Because there is pretty much never the number of reserves required I have found it impossible to drop a trip with PB days. Occasionally they might have sufficient coverage to drop a reserve day (worst use).
Understand the A350 is a whole different story. With 15 hour days, these PB days are powerful.