I do not want to sound like the "Well it depends" guy, but it really does. What device will you begin to test it on? 100 lvls? That would require 100 layouts, but the amount of layouts and performance don't go together. It is what's happening within the layout, that will effect performance. 10-20 objects? That does not seem like enough to effect performance. I've been prototyping a few games in the past with about 50+ physics objects in a 0 Gravity setting, with the collectibles spawning particles and the performance did drop into the 40s FPS but anything below was rare and the reason for the FPS dropping was the particle spawning.
The testing was done with my HTC One M7, via the CocoonJS App Launcher. Since then, I haven't done any testing with physics, since I've found the "Bullet" behavior to be a better choice for the game I'm creating.
So no, I do not think you will experience serious performance issues if you know what you are doing.
Then you've got the whole "Construct 2 games on mobiles have terrible performance!!!" across the C2 community, but strangely and fortunately I haven't experienced that yet.