Answers
1) No. The levels will all be different. This is how it should be.
The figures reflect the amount of volume adjustment required at each speaker so that the sound is an equal level at the measuring point. IOW, if one speaker is close, then its level will be lower than a speaker further away.
2) sub volume is notoriously difficult to measure with any degree of accuracy. The best advice is to adjust by ear. Bear in mind that "most people" expect the bass level to be set far too high. If it is then the bass will be boomy and will dominate the sound balance. The ideal is that the bass notes start and stop cleanly with the on-screen action.
You can make adjustments to the sound after the speaker calibration wizard has been run. I often find that lifting the centre channel by 1.5dB helps make dialogue easier to follow. You can adjust sub-bass up too.
