Probably because the HR DVRs don't do 1080p60. They do 1080i60 or 1080p24.
Funny, I don't remember saying the HR did 1080p60.
The TV will render then 1080p24 stream at 1080p24 @ 60Hz if it doesn't support another evenly divisible refresh rate (such at 48Hz or 72Hz). In my case, I can choose from 1080p24 @ 48Hz (flicker, but evenly divisible) or 1080p24 @ 60Hz (no flicker, but displayed with an uneven divisible refresh resulting in a frame unevenness). Refresh doesn't affect the frames/second being fed by the HR. It's always 1080p24 on the 1080p24 channels.
I prefer @60Hz since the flicker really annoys me. Going to the V10, which supports 72Hz, is even better since it's even divisible *and* flicker free (but I didn't feel like spending the premium for that over the G10).
Either way, the info on the TV should show 1080P on 1080P fed channels/sources.