Most Mid to low end D1 schools are simply going to have a lower RPI and SOS by the nature that they play the majority of their games vs SIMs (12-16 Sims in a conference). That does not mean that they are less of a team. To make a fair, and probably impossible, comparison it would need to actually look at who they played (and home or away) and how they did in those games.
The 12-15 might have won 8 of their 12 wins against non conference SIMs and only won 4 of 16 (you have Team A playing 27 games and Team B 28).
It maybe a matter of personal preference for the PIT. As I have stated; I feel that the Team A's, who I would wager is already getting benefit of prestige and large conference money for recruiting, should also not get a post season bump for being mediocre.