New Floodlight Cam Plus has terrible mounting plate

I've been installing Floodlight Cams for two years now, and the new plastic mounting plate is awful. It warps when tightening the center screw, which is the only option to mount it now. The metal mounting plate was much stronger and provided several holes with which to mount it to different types of electrical boxes. It is impossible to mount it flush to an existing box such as this one. The old version was a 10 minute install. Now, I need to go and replace the perfectly fine electrical box with a new one that will work with this very limited new plastic plate. Very upset and disappointed in the new, cheaper mounting system.