It's probably just to spread the VO3X around so they form small
minorities in service fleets, that way more services can become
WAB. 74, 107, 153 and 161 have too many VO3X to become WAB. Maybe
those SLBP services still can accommodate one or two more non-WAB
buses to increase capacity / frequency and yet still meet the WAB
quota.
But I do think the VO3X should go to JIS rather than those
services that serve the city and residential areas. Just in case
the WAB quota needs to be raised to serve more PIWs. Surely there
are way more PIWs in residential areas than there are in industrial
areas (if any at all).
Would be nice if 9508 and 9662 can remain with 161, but ah well.
Anyway I'm just speculating. No real idea what's going on since I'm
just a casual observer.