If you end up in a tie with somebody but lost to them both times you had your shot. You blew it.
Remember how we all felt about last year because we were as tied as we could be with Michigan based on opportunities but we beat the dog sh— out of them so we felt like we were the true champions?
By that logic, if you beat someone both times but still ended up in a tie with them, you also had your shot and blew it — you went 2 games worse over the rest of the season.
I think the more important consideration, though, is situations that are less obvious. We beat MSU at home by 1. If we tied with them, and one insists on not having co-champions, should we get it based on the head to head win, even though a 1 point win at home is roughly equal to a 2-3 point loss on a neutral court? What about situations with a split season series — is having a co-champ really worse than breaking a tie with record against, say, 7th place Iowa who one team played at home and the other on the road?
Co-champs works fine. In the B1G Tourney, where seeds must be assigned, the tiebreakers work too.