Unity Tree issues on Android

Hello,
First post here. I’ve a bit of a problem. I’m building a scene for my i9100 which consists of of some terrain / bush’s and tree’s I’ve spent many months building tree’s and this set (almost 8 now) now I’ve tested slightly as I went along and I know I’m building my tree’s correctly and they are animated using the wind zone component and DO work.

Problem is this. Some of the tree’s wont Animate at all (but do in the editor and have worked fine in the scene before I populated it a bit more heavily) And some of them Animate only a little bit.

What am I doing wrong ? is there something to do with a vertex deformation limit on my phone ? a bug in unity ?
I should mention my FPS is 40 to 60 also.

Please help. I’m at my wits end. I don’t want my project to die lol

bump

anyone have any idea ?