MeshColliders count limitation on Android for Coin Game - Perfomance - low fps

Hello Everyone,
My current project has only one scene with a moving platform on which I instantiate coins (Cylinder mesh) then, a wall hits the coins inn order to push the coins to the goal (a coin pusher game basically).
Things I've done:
1 - Add Mesh Collider (Cylinder) to the Coins, convex.
2 - The floor is a box collider
3 - The pusher wall is also a box collider
4 - All the Instantiated coins has the same material, texture, scale, rotation and they are combined as soon as they are created.
5 - Configure Physics for Min Penetration to 0.001 (in order to avoid overlapping) and solver count to 10
6 - Coin model has 8 faces with no texture (I've removed it to improve perfomance).

My Android testing device is a Huawei Honor 2
CPU(Huawei K3V2 Quad-core 1.4 GHz Cortex-A9)
GPU (Vivante GC4000)

The current FPS (by Script) count I'm getting with 80 coins is 35 in this device. But After I insert some coins and the collisions begin to generate, the FPS are dropped to 15 then 10, etc...

After remote profiling the android runtime, I have extreme high Physics.Simulate (70%) and Overhead(10//20%).

Questions:
1 - Are these FPS normal for the described HW?
2 - Are there any way of optimizing the physics approach? Maybe using 6 box colliders for each coin?

I would really appreciate any help.
Thanks in advance.

 

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