RippedMan said: "How'd that work with like American Psycho which seemed all electronic?
The AFM takes it on a show-by-show basis. A few shows were written to be performed by small combos, less than the theatre's required minimum (Rent comes to mind). Back in the day, the theatre used to have to hire people to show up and just sit in the pit during the show, not playing a note, just to satisfy the minimum. Nowadays there are ways around that, and if the essence of the show is written to be a certain way, they can negotiate with the AFM and skirt the usual requirements.
What they can't do, however, is change things once it's been open and running for so long. So it's not really a "good for Phantom" situation; they pretty much have to keep running with the same number of musicians they had in 198-whatever. And believe me, some of those same musicians are still there...