they way i did it was ppl<ME<IR<MEC
next is the MEI then CFI/ASEL Commercial addon
that way all the twin time i logged for my IR is PIC as well as for my MEC ride. I did my instrument in the twin as well. All i had to do for my MEC was stalls, steep turns, slow flight, and short field take offs and landings. Most people do every thing in a single so there MEC ride is alot of work. Not only do you have to do all the multi engine stuff, Vmc ext, but you have to do a single engine ILS to hold a Multi Instrument rating. and then you also have to do the commercial maneuvers. Not to mention that the oral will be quite a bit longer when you have to get into Multi engine aerodynamics in addition to all the commercial questions. Thats a lot of work for one check ride. The way i did it not only spaced all that work over three different checkrides, but i also started logging multi engine PIC very early on. My advice to you, is to get your ME add on asap, you will thank your self in the long run.