I agree with the factory reset thing, but there is clear instructions on page 42 if the OP wants to just do a quick check to satisfy his, and our curiosity, prior to re-running Audyssey.
owner's manual page 42:
View attachment 29327
As Ryan pointed out earlier, the UF5 has quite low sensitivity, and 4 ohm nominal, the combined effect can be seen below:
View attachment 29328
So there is no way the OP can hit reference level with the system he has, but if he's happy with 78-80 dB average and 20 dB on top of that, the system should be able to deliver, given that it is only a 2.1 system.
Aside from the system being limited by the output capability of those speakers, the main culprit appears to be the relatively low output from his cable box (is there a volume control button on the remote?) as he seems happier with other sources such as the X Box.
I would suggest the following:
1. Sitting closer if possible, say 9 ft instead of 10.7 ft.
2. Check the impedance setting, better still re-run Audyssey as suggested, to make sure it is set to 8 ohm.
3. Set crossover to 100 Hz, the sub has f3 at 148 Hz, so take advantage of that.
4. Angle (toe-in) the UF5 to make sure they are pointing to the main mic position
5. Turn Dynamic EQ on, use ref 0 for blue-ray movies, ref 5 or 10 for cable box, or music listening..
6. Make sure "ECO" is "Off".
Re-run Audyssey will take care of 2 and 3. It should be quick and easy to do for a 2.1 system. 5 is important for movies if listening at 5 to 10 dB below reference level. It is better than bumping up the sub level by 4 dB. As HD said, how much to bump up is a matter of taste, but any such bump is applied across the board regardless of the volume position and frequency, whereas DEQ is dynamically done to restore the balance to that intended by the mix.
Edit: I added item 6, that needs to be checked too.