Android Game Optimization

Im doing some optimizations on current game project. I did everything i could find in my code to optimize and re-organize it. Now as i can see most of perfomance cost is caused by graphics/rendering? Because all big spikes are green and green area is larger, blue are code. And difference is huge. Is it normal that rendering area is this huge? Any tips for me?

Some small info:
I have about 20 planes with alpha/transparent shader and 1 ground plane same as them. There is of course other models but this ones are using alpha/transparency does that cost much? Game is running smooth on newer phones, but im trying to make it smooth for older devices and it just need a little bit more optimization to be accomplished.
For example on tablet Samsung GT-5210 i get about minimum 25 FPS and user can see some small anoying fps drops.
Tablet is 1GB RAM, Dual-core 1.6 GHz
And for “higher” devices like my xperia z everything is smooth
I would like to give you guys apk to test the game, but company rules doesn’t allow me to share it.
I also use NGUI
Hard Shadows
And all shaders are from mobile category
Game theme is endless running
Vsync is off

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Transparency kills performance in mobile devices. Specially with those devices that have high resolution display but poor GPU.

Thanks on tip i appreciate that