Fletcher would be done for after the concert either way.

He only planned on Neiman playing the first song, "Swingin." After that he kicked him off stage and was going to get an alternate to fill in on drums. It was only one short intro song and yes it would potentially harm the competition (was it a competition?) but one song wouldn't destroy an otherwise stellar career. Also Neiman didn't do too horrible at improvising the song, so a normal audience wouldn't have even cared or noticed. It was purely to sabotage him in my opinion, but I'm sure many will argue that it was also his hardest "test" of sorts, and that's a fair opinion to me.

Are you suggesting Neiman would tattle on Fletcher ? Who would he even tell? Why would any one care about misplaced music sheets ? It'd be hard to prove. And after that life changing performance for Neiman and Fletcher , why would anyone of them harness resentment or seek revenge? It was probably the best moment either of them had in their life.

Other than the press, I don't know who Andrew would tell. This was a commercial concert. It wasn't a school function or a supervised competition. It was part of a larger jazz concert,

Fletcher had already been terminated from the Conservatory. He was on his own as a solo artist(like in the jazz bar) or conducting a band, made up of musicians of his choosing, with no oversight from anyone.

Other than the press, I don't know who Andrew would tell. This was a commercial concert. It wasn't a school function or a supervised competition. It was part of a larger jazz concert,

Fletcher had already been terminated from the Conservatory. He was on his own as a solo artist(like in the jazz bar) or conducting a band, made up of musicians of his choosing, with no oversight from anyone.

I really think he thought it out. If Andrew gets discouraged and quits, he accomplishes getting his revenge on him (you hear Fletcher talking to the audience and making fun of him, by saying something like "our drummer went a little too avantgarde"). Otherwise, he senses (in his mind, he KNOWS) he's going to be one of the great. Or, at least, he deems Andrew being his best shot at "discovering his own Charlie Parker". Therefore, while Andrew gets back, plays a great "Caravan", and then makes the audience go nuts with his drum solo, Fletcher knows he's going to be "one of the great's mentor", and that he's going to become a great media story, a "lovable villain", like Jo Jones was to "Bird".

Knowing how obsessed he was about his reputation, his final act of revenge doesn't ring true.