At his blog today, he vents about this latest item on his "increasingly prolix and impossible-to-catalogue list of pet peeves: confusion about federal sentences." It's a really instructive read, and I recommend it.
For the record, I do understand the difference; but the threat of a theoretical sentence that amounts to life in prison is intended to scare the bejeezus out of the defendant in this case (and others!). As a threat, it's worth noting. No, I doubt he'd actually do that time if convicted and sentenced.