They state that it is! Its a CAB SIMULATED DIRECT OUT! the cab sim imitates the physical speaker. two paths out of the transformer, one to a real speaker, the other to a cab sim (speaker replacement)...
Yeah, I think you're right. I think perhaps we need to step back and kind of look at the bigger picture again. Remember that the DT amp itself contain all the amp and cab modeling that the POD HD does, for starters. When you use L6 Link with the DT in full volume mode, no modeling is being done in the DT itself, except for what happens to the XLR out. You have the preamp signal coming through L6 Link, it hit the power section of the amp in whatever way it configured, goes to the output transformer and out the speaker. The signal going to the XLR out would have cab and mic modeling applied in the DT amp itself before it leaves the amp. This is essentially having two layers of cab modeling if you have the Cab on in the preset in the POD, but, really, you have that with the real cab, too. In the combo or stack power amp modes, the cab modeling from the POD is more re-voiced, anyway. It's really more like an EQ applied to the signal to give the flavor of the amp being modeled.
In LVM, nothing changes on the POD side. The DT, however, bypasses all the topology, class, and other settings associated with the real power amp. Those settings still affect the sound, but the power amp is now being modeled. So you have the POD providing the pre side of the modeling and the DT providing the power amp modeling. Hugo said the cab model doesn't change on the XLR out, and that makes sense. That doesn't mean the output would sound the same, though. It might be very close, but it should be a little different because in full power mode, the signal going to it is going through the real power amp, and in LVM it's going through the modeled power amp. In either case, there's another lay of cab modeling applied to it. The signal is still tapped off the output transformer whether the amp is full or LVM.
This is at least how I understand it to work. I'm, of course, open to correction.