But the thing with the IR is that there are no surprises, whereas the CPL "can" be more vague, so hence if you are not used to the twin it can get out of hand.
I hadn't flown twins before my ME IR and I didn't struggle with the transition, you will learn most of the procedural side of flying the twin in the sim anyway, so jumping back in the twin after the sim is no problem
BR, I have absolutely no idea why I have Probationary PPRuNer on my title, as it always used to be different, I am wondering if I have been naughty