A FlyerTalk Posting Legend
Join Date: Sep 2009
Location: Minneapolis: DL DM charter 2.3MM
Programs: A3*Gold, SPG Plat, HyattDiamond, MarriottPP, LHW exAccess, ICI, Raffles Amb, NW PE MM, TWA Gold MM
Posts: 100,413
I'm confused. You can't just "drop MNL." If you no show for a segment, the entire remaining ticket will be cancelled. I also don't see why the price of DPS-MNL should matter as it's not on your current ticket, nor would you be flying through MNL on the new ticket.
Note also that not all airlines interline with AC, so you can't necessarily add a cheap segment from SIN.