There are two ways to win promotion, one way is to win the playoff final, the other is done by BB when they are doing the bot cleanup.
Even though SS is a bot, he won the division and was hence promoted. If there are any bots in Div II, they are then replaced by teams in Div III by rank, which is determined by W/L, hence if anybody would have been promoted in Div III.5, it would have been PP. As it happens, there are other teams in III that had better records who didn't win the league and were promoted.
Lame I reckon, but hope that clears it up