I just tried it and it only takes up one tuner. Very nice!
The Hopper has a 4th "tuner" if you will. Weeks ago, were scratching our heads trying to figure out why a Hopper can support 3 Joeys.... that is, 1 Hopper + 3 Joeys for 4 TVs.... when the Hopper only has 3 tuners. The 4th is limited only to playing back prerecorded stuff. That includes PTAT. All recorded stuff is stored somewhere else, and I believe PTAT is accessed through internet download. It's just so fast now that "buffering" is now a thing of the past.
Or am I wrong?