Don't have an answer to your question but wanted to note the following:
- Delta's Basic Economy does not provide any MQMs or MQDs
- For many main cabin fare classes, MQDs will generally be better when booking via Delta unless you find a good deal or are flying very far. For example, the R, G, V, and X fare classes only give you 5% MQDs for distance flown. Not sure where you're originating, but if you flew SEA-CDG-ARN-CDG-SEA that's a bit over 13,000 miles flown RT, which would be a bit over 650 MQDs. If you originate from JFK instead, it's a bit over 9,000 miles for a bit over 450 MQDs.
- Don't forget about free changes with Delta when booking Main Cabin. Even if you are confident that your plans will not change, this is still incredibly useful if the price of the flights go down. On a recent trip I did to MXP, one of my friends booked BE while I booked Main and the price of the flight dropped by $150, so I was able to "modify" my flight to the same flight and get $150 of eCredit so my ticket actually ended up cheaper than his.