If you adjust the sub to be in phase with the mains when using the digital crossover on the 950, and then switch to the 80 Hz analog crossover for the 5.1 inputs, the sub is now approx 180 deg out of phase. About 4 other people have confirmed this
As you know, it can get quite obvious when the sub is phase inverted from the other speakers: the sound seems to drift all over the place.
This was a problem in the original 950. I hoped they'd fix it in the blue dot, but I guess not.
I have to physically walk to my sub and invert my sub's phase switch in back, when I switch mode in the 950, or else the sound is drifty.