I'd normally agree, but I think in this case I'd go for the shorter layover not being right before the international flight. If you miss the MSP-DTW flight they'd probably be able to reroute you at that point (~2pm). If you miss the DTW-FRA flight your rerouting options might be limited at that point (~6pm) and could result in not being able to get on a TATL flight until the next day. Additionally, passengers are required to be onboard 30 minutes before an international flight but only 15 minutes before domestic flights. Of course YMMV on enforcement there.