Actually, 5-3 in bowls. However, two wins & all three losses were vs. top 25, so 67% of league got bids and fared well considering ranks/matchups. (I have no clue about the point spreads, I’ll trust your analysis on that).The year Texas won NC in 2005 the media narrative was that the Big 12 was weak and Texas dominated it.
The truth was Big 12 was best league by miles that season. 5-1 in bowls and 6-0 vs the spread and I don't know that any of the games were even close against the spread. ISU was the only loss and we lost by 3 as an unranked team playing against the #14 ranked team.
Wins:
Kansas (over Houston)
Missouri (over South Carolina)
Nebraska (over 20 Michigan)
Oklahoma (over 6 Oregon)
2 Texas (over 1 USC)
Losses:
Iowa State (vs 14 TCU)
Colorado (vs 23 Clemson
18 Texas Tech (vs 13 Alabama)