Seems you did get a bit of a bulk discount if you were with all 4 for the full hour, so that's good.
Personally, while I aspire to 3 at a time someday, I feel like the marginal utility of a 4th is limited unless one of them needs a break.
Then again, if FIV is on the table, I do have a mouth, 2 hands and a gavel, so maybe? My problem is I dont think I could possibly play 4 separate instruments with 4 different rhythms. Everyone needs to be in sync!