With Y & H fares, you could have just joined AAdvantage as these are the booking classes which you can earn miles on.

You would have to pay the $50 if you want to join MPC. What may happen is that you will be fast tracked to Silver immediately.

How did your wife get MPC complimentary? Then maybe a phone call to MPC and state that since your wife got MPC free, you should too and you flew even more than she did.