To be honest with ya, I wouldn't chance it. You don't know if you are the first stop for DME or the last. When we flew home a few weeks ago, we were the last stop for our particular DME. The bus was packed. There were obviously a couple resorts that were picked up before us, each at least 15-20 minute stops. There goes any extra time you thought you had.
Then, once we got to the airport, there were multiple drop offs so if you weren't at the first drop off, you had to wait for everybody who was to get off the bus and get anything that was stored below out before DME went to the next drop off. Those 2 things alone would make me question whether or not to mess with the time. What if you mess with your pick up time by one hour and come to find out when you get on DME that you are the first stop and there are 4 or 5 more resort pick ups after you. There's that extra hour that you thought you were going to waste at the airport gone, and now you're running late.
Also, the security lines at MCO can get backed up like nothing I've ever seen.