We're looking at going to a couple podunk beach towns on the Pacific coast of Mexico. The hope is to fly into one and out of the other. Connecting through Mexico City in both directions with the MEX <=> beach towns being flown on Aero Mexico. Pricing using "Multi-City" on dl.com yields fares over twice the cost of individual 1 ways. On AM.com its about 50% higher. Is this one of those situations where the airline gets mad if you book 2 separate tickets? Any chance dl reservations could price it to give the lower fare? As a whole other can of worms, is there benefit to booking on Aero Mexico for medallion qualification?

Thanks in advance, I appreciate your patience