There is sometimes little logic in how some fares are calculated and I suspect some of this is down to computer algorithms. For instance tomorrow if you wanted to fly from London to New York you can find economy fares from as little as $500 through to a codeshare priced at $11500. Now I cannot imagine anyone would pay that $11,500, nor do I think the airline would expect someone to pay that, so it would seem that somewhere along the way an algorithm has produced the exceptionally high prices, perhaps because the fare buckets have limited availability.
It would be interesting to meet the people who come up with the airlines fare pricing structures, but I suspect that much of the information is kept strictly confidential.

Then you will earn zero MQM's. As covered in the partner earnings page, KE coded flights do not earn MQM's.