Perhaps Iím misunderstanding the topics discussed but I can assure you I can go in and out USB, or mix them with 8 x MIDIPorts to configure my needs any way I want.
I run multiple editors, or just use an iPad + PC for 2 separate editors, or any combination on offer.
MIDI In USB out, USB In MIDI Out, USB In USB Out, MIDI In MIDI Out, and multiple flash drives too.
Perhaps the K4 is an exception to the rule.
I couldnít do without either of them, thatís for sure.