Bubba's show is completely different. He does 2 different shows, one of which is in limited FM markets. The proposed Howard FM/Sat venture would be a simulcast and the FM side would more than likely not be in limited markets. Given Howard's name and the desperation of FM, I would guess he'd be given at least as many markets as he performed well in before.
Edit: See the thing about Bubba vs. O&A, Bubba didn't forsake his sat listeners in order to cash in on FM. No matter how careful you are, the FM side is going to want to censor content and add commercials. This is what was predicted would happen to O&A, and it is exactly what happened. FM sensitivity overtook all decisions, and the non-Kool-aid drinking XM fans realized they were getting screwed.
I said before that if Howard ever went to a simulcast FM/Sat show, I'd cancel because those paying for the Sat side would be getting the shaft. I feel that way even more strongly after seeing O&A fans get the shaft on XM.