"For travel prior to January 1, 2015: Pay with Miles tickets booked in Main Cabin are not eligible for mileage accrual and will not earn Medallion Qualification Miles (MQMs), Medallion Qualification Segments (MQSs) or Medallion Qualification Dollars (MQDs). Delta One™, First or Business Class tickets purchased through Pay with Miles are eligible for mileage accrual, MQMs and MQSs and will earn MQDs for the portion of the base fare and carrier-imposed surcharges remaining that is paid in currency after miles are applied to the ticket total."

https://www.delta.com/content/www/en...ith-miles.html