They are still putting it on 101W, where there is no capacity for HD left. I'd assume they are shutting off a bunch of PPV's to allow for it. It could be in MPEG2 but if they were smart they'd put in MPEG4 mode so they don't have to shut off a bunch of PPV's. It doesn't take a whole lot of room for a MPEG4 720p feed.
It would make more sense to put everything in MPG4, but D* still has a lot of MPG2 receivers out there, that need to be replaced. I don't think they will put any Nationals in MPG4 until they replace more receivers. MPG4 will probably be used for locals until such time they are all replaced.
It would be interesting if anyone has the figures on how much MPG2 vs MPG4 receivers are currently activated, by D*. Remember all the HR10-250s are MPG2, and there are still plenty of those being used.