But if pit has to play a 163 and loses, than the Giants would have a better regular season record (again, assuming StL, Pit and SF all have the same record after 162).
Lets assume that all 3 teams finish with a 92-70 record. Pit and StL play a 163 to decide the central division. The winner ends the reg season at 93-70 and the loser finishes at 92-71. 92-70 is a better record than 92-71, so the Giants host.
They mentioned it during the broadcast about ties in the wild card. Head to head determines home game. we won the head to head with St Louis but not Pittsburgh.