Originally Posted by
hhdl
It's based on the post-discount award price. For PWM (which will nearly always be a better deal than miles + cash if you have a DL Amex), the cash portion earns MQD normally and the mile portion earns at the 1 MQD per 100 miles rate.
I don't recall how the miles + cash option earns. It might be as the award flight that you're buying miles for or it might be as if it were PWM.
As shown in example above, MQD earn on Miles+Cash awards is a hybrid based on miles used from account and the cash used to purchase additional miles to cover the award redemption price (325 + 90 = 415 MQD). You are getting MQD at 1:1 ratio for cash part, but you aren't really getting anything of value for it. You also get 1:1 MQD for FCM upgrade purchases, but you are also getting something of value for your purchase (an upgrade) and not just additional MQD.