I did a multi-CPL and yes, it is a big jump from a slow single. The multi hours allowance in the training for me didn't leave me enitirely comfortable that I would pass the skills test 1st attempt. However, another hour with an instructor ensured I passed first attempt.
My thought process for choosing the multi-cpl vs single, was that when the IR came around, I wanted to be ahead of the game and feel more comfortable on the a/c than if I was learning a multi and IR procedures. Seemed to work for me.