Ah ah! Maybe I’m totally unclear 
I got the OT a few months ago so I may be wrong with the terminology?
For this “trick” I use both pLocks and scene-locks.
Scene-locks seem to “force” or override the trigs pLocks, on my OT anyway.
XVOL doesn’t need 2 scenes, if scene slot A is deactivated, track amp VOL is defined by the part’s track’s amp vol parameter. The silenced trigs won’t play as they are plocked to xvol=-64. If scene B is active with a scene that scene-locks the track’s XVOL to MAX, then moving xfader to slot B will make the silenced trigs actually play, at the volume defined in the part.
I’ll have a look on my OT, perhap’s am I wrong somewhere lol