Instance static mesh performance Unreal engine 4.12.5

Hello everybody,
I have a problem with Unreal Engine 4.12.5. I’m creating a game for IOS and Android devices. My map is composed of a series of Blueprints and each of them has static Mesh Components which form houses. My problem is linked to the performance. I’ve read that in order to improve the fps number I should turn the static Mesh Components into instance static Mesh Components. For this reason, in each blueprint I’ve created instance static Mesh Components and for each type of mesh I’ve added the instances through the “Add instance” option. The problem comes up because performances have decreased instead of rising up. I’ve even tried to add this project (Convert To Instances in Blueprints - UE Marketplace) which should automatically turn all static Mesh Components into instance static Mesh Components but without success. It seems like the 4.12.5 version has some problems with the instance static Mesh Components. Is it so? Can you please help me fixing this problem? Thanks a lot