Problem with hovering of stacked custom meshes

[sonykay]

I made a replacement mesh for carton of cigarettes you can see here:http://newvegasnexus.com/downloads/file.php?id=37339

but now the cartons hover if stacked ontop of each other on the map (for example lucky 38 has lots of them) and stay like that until player touches them

any ideas how to fix this in NifSkope? which variable to alter?

 

i attached a screenshot of the situation

please help