Everything that I can find in the contract points to a 320 category pilot being paid 321 pay regardless of what is flown or how much is flown. Example reserve guarantee is 80 for June and you fly 50 hours. The entire 80 hours would be paid at a321. Which I think is about $5 more per hour. PWA section 4 C.1

Others have said only the amount that is guarantee is paid at A321 (80-50=30 x 321 rate)?