Join Date: Jan 2008
Location: NYC, NJ, Long Island
Programs: DL DM, 1.6MM, UA Silver, NEXUS, SkyClub & AdmiralsClub Lifetime, Bonvoy Titanium
Posts: 6,645
You're probably better off staying at PM and rolling the MQM's.
Buy 2 one way tickets. They may price a bit higher than the RT but you can credit one to your FF and blow off the one that would put you over the DM threshold.