Bussing with PT

[Vedderman]

Hello everyone, I've received and read in many places that PT is vvery "weak" in bussing, actually if you check out Manley's web site and look for the 16x2 mixer it says that "PT has one of the strongest individual channel processing capabilities with all the TDM plugs available, but it also has one of the weakest mixing busses due to squeezing most of the DSP into the channels. They left very little to deal with the buss requirements, which means, that every fader at less than the highest setting, reduces bit depth, so you are not mixing 24bit signals, you are mixing 20 to 12 bits typically"....and so on.....can someone make this clear?....do they mean mixing to 2 tracks or mixing channels alone?
Thanks a lot!