Windows Phone performance

Hello, I have a simple scene (see the picture, the FPS is from editor). It runs perfect on android or pc, but the framerate is very poor on my Windows phone device (Lumia 925). The graphics is very simple, but there are some rigid objects in the scene (every red cone is rigid). Physics quality is set to the lowest quality. Materials are mobile/diffuse, some of them are mobile/bumped diffuse. When I profile the mobile device, I see a lot of overhead. I presume, that this could be one of the reasons. What could cause the overhead? I use javascript scripts and there are some sendmessage calls in update routine. Thank you for your help in advance.

Actual mobile profiler plot: ][2]