is there a code section in 430 that discusses running line and load in the same pipe from a motor disconnect?
That is only a problem if you are installing service conductors not motors. You may have to dertae for conduit fill.
Any installation where conductors are installed in a raceway that is possible.Not "may", you "have to" derate the conductor ampacity.
The reason I don't like this type installation is that we end up with live wires running parallel with conductors that have to be 'de-energized' in the case of LOTO. Should there be a contact between two wires of the same phase.......