Troubles optimizing my game(batches)

Hello.

I'm in desperate need of help with optimisation of my game. It's going to be a mobile game. I'm having problems with heavy spikes when It's displaying a larger part of the level.

I tried two methods, one using the static batches and one combining mesh with AdvancedCombineChildren script. I'm having better results with the second one but it's still a nightmare.

Here is a screenshot showing stats for both of the methods: (combining top and static bottom)

As you can see the spikes seems to occur when the batches grow up. What i don't understand with the combining method is how i'm getting such a high number of batches while the SetPass calls growing is not that much.

Plus why the static method still makes that amount of SetPasses/Batches while all of the materials are exactly the same (it says it's saving about 1k of batches but there are still 1k not saved).

On a side not I had way better results before today. I don't understand why now it is so bad when all I did was supposed to optimize my game. A lot of inconsistents results makes me creazy. I will work on this question today.

Please help me!