D 75 teachers don't get to vote in the actual divisions where they teach - the divisions where retirees don't get to vote. Thus, their votes are almost irrelevant when buried in the functional division because they -and other functional units get buried by the overwhelming retiree vote.
When the oppo was buried when Unity got 85% of the vote it didn't seem to make sense to bring all this up. But once they slipped into the 60s and the oppo reached a third, the potential to actually win seats in not retiree divisions becomes possible. It D 75 was moved to divisions