If your mesh is good on the other floors, youc an still use groundspawn plugin.
I would manually run my rogue up to that floor with ground active off, then once i was upstairs or on the floor I wanted, issue (i believe) /ground invalid reset, to reset any and all invalids in the zone. Then turn him back on. Now he'll see the lower floor as invalid, and work the floor he's on.
Doing it this way is still a headache for some zones, though. Lookin at your ToFS