Yeah that makes it a bunch better.
Mence comes in, takes SR, threatens with Draco Meteor to kill. If you switch around you either lose a pokemon, a lot of % off of one and then some on another, or a bunch off of your revenge-killer since it's a steel(Jirachi, Scizor), and it can't come in again. With SR and 2 turns of LO, he just lose only 45%. In comes Scizor: move out.
Next time he comes in he's at 30%. Likely your team is even MORE weakened so it will be even easier to threaten with Draco Meteor. If you try to sacrifice something else there's even a chance of it Roosting, leaving all the power in the Salamence user's hands. Even if you predict correctly and switch when he attacks, you bring in Scizor and KO it. Congrats: your down ~1.5 pokemon and took out one. Then there's stuff with SR since Scizor is down by at least 25% being forced to come in twice: and if SR is assumed on the mence side, why not on the other side as well?
I hate myself right now.
Edit: If your a baller, you would Pursuit on Mence after the first Draco Meteor. That's actually a really cool idea.