"Ah, yes, but the original post did say the finale was "changing." A finale, as I understand it, is pre-curtain call. So to say it is changing would mean perhaps replacing "This is My Story."
Well, I guess there are two ways to read it then. But, I highly doubt Shrek would eliminate an original song that perfectly wraps up the show to make room for "I'm a Believer." Especially for a pre-curtain call, as you mentioned. It just doesn't make sense.
"We like to snark around here. Sometimes we actually talk about theater...but we try not to let that get in our way." - dramamama611