Hi all,
my guess is it is Standard/General MIDI implementation, CC in the 70+ range are defined towards "Sound Engine" Parameters like Filter-EG and the 74 is this "additional LPF Cutoff". OB-6 is also CC 74 on the Prophet 12 there was no more room in CC, in Sysex it is implemented. Would be good to have for opening Filter via Pedal and other controllers.
Might be more usefull in playing and realtime control (external LFO to CC74) not so much for editors.
Hope this helps,
Martin3