simple math says you get the same thing by kicking the PAT (going up 12) versus getting the 2 point conversion (going up 13) - the net result being you require the opponent to score 2 TD's to beat you.
By missing the 2 point conversion (leaving you with a 11 point lead), you open yourself for a potential tie via FG and TD with a successful 2 point conversion).
Kicking the PAT was the correct call. The Rams blew it.
