BUD stands for big ugly dish. Usually for C-band it's 8 ft or larger. The Ku is usually .8 meter or above. Both of these are linear polarity signals. Where as the DBS/FSS (Dish Net) are circular pol signals at different frequencies of the KU band. These DBS/FSS are higher powered sats than the C-band Ku band "BUD" dishes.
Absolutely not. What led you to think that? Not that it's unfathomable, and it could make some things a bit simpler if the switch had an integrated diplexer, but it doesn't follow from what you've been told. Seriously, what was the source? The answers you've gotten here have been correct.