Yes indeed, on Delta a second bag that is both overweight and oversized can cost you $315 in fees when they get done. $50 for it being the 2nd bag, $90 for being overweight on Delta (51-70 lbs) for domestic flights, and $175 for being oversized. On United it is $50, $125, and $125 respectively for $300.
Delta Excess Baggage Fees United Excess Baggage Fees