actually in the big group you get 8 ap.

I only waste the 22 mp for level 5 doom if there's a large group. Otherwise I have everyone except Lenna dance and hope they don't use tango of temptation or mystery waltz more than twice. (lenna has a cure staff so if they don't use jitterbug duet she's there for backup and the occaisional Raise or Esuna)