he would have done the full songs in concert but to fit it all in a movie they had to shorten most of the songs.
for BOW he would have only done the one verse because we saw him instructing the band to play according to that but the others were cut due to time constraints for a movie i believe
And Man In The Mirror :S I think he sang the whole songs but kenny clipped it away so it would fitt in the movie
There must've been a problem with the start of MITM - they wouldn't have just interviewed the back-up singers and plonked it over the top. Just like when he messed up at the start of BoW, they had interviews over that and cut to "let's do it one more time". It wouldn't have anything to do with length as it would have lasted for as long as the original rehearsal.
he didnt mess up BOW? it was the band or something that did not make it right or something in the beginning of BOW not Michael
He stops singing and says something like, "Oops, sorry, there is no second verse".