Confounding discrepancies between partners
 

I just booked a BOS-TOL roundtrip for tomorrow (29 Aug) returning Monday (1 Sep.)

DL (FO status, and I have ~350k miles already parked there): 25k miles + $49 taxes/fees + $150 last-minute ticketing == $199 in fees

CO (no status, didn't even have a OnePass account until about 30 minutes ago since I've always credited to DL, then created one and transferred in 25k miles from Amex): 25k miles + $10 taxes/fees + $75 last-minute ticketing == $85 in fees

Same NW flights. (I think NW didn't even have a late ticketing fee, but Amex doesn't go to NW, and I've never transferred SPG to NW so I was a bit hesitant to do so for last minute travel.) Yet one, even with no status, is less than half the price.

In this case, it's indeed a shame that CO seems to be headed to *A, since they seem to want to redeem my miles without being quite so evil as DL. I just don't get why different alliance partners can charge such disparate amounts for the same flights, especially US carriers domestically.