Posting an update for the benefit of others - it took a little over a week for my charges to finally show up under the Amex web site tracker that confirmed I crossed the boost threshold. I received an email from Delta that morning saying "
You’ve Earned 15,000 More MQMs With Your Card". I immediately claimed my MQM's and now I am just waiting for them to show up under my profile on the Delta web site. In case anyone needs the link again for claiming the MQM's, here it is. https://www.delta.com/acctactvty/redeem.action