While the chart only mentions miles as changing on February 1, I can confirm that MQD earning on KL 074 tickets w/KL-coded flights has also changed from mileage-based to spend-based (based on flights taken at the end of February). Not terribly surprising as they would have to know what you paid in order to calculate spend-based miles. I'm MQD exempt based on AMEX spend, so I don't really care.

Note that any 006 DL ticket will earn MQD/miles based on spend regardless of the operator or coding of the flight. This has always been the case. You need to carefully read the footnotes section -- "(1) Partner-marketed flights that are not ticketed by Delta will continue to earn miles based on a percentage of distance flown* as determined by the fare class paid" and "(3) Medallion Qualification Dollars (MQDs) apply to Medallion qualification. Flights marketed and ticketed by the partner will earn MQDs based on a percentage of distance flown* as determined by the fare class paid." In other words, the KL charts for miles/MQD's do not apply to DL 006 tickets.