Not so sure about that. I would think that an over torqued countersunk screw could cause a crack easier than a flat bolt head. I realize that I'm comparing apples to oranges ( plastic vs. steel ) but I saw so many leaking neutral switch plates on RDs due to cracks from over torqued C/S screws. The key was loctite and just snug the screw enough to seat the cover and compress the O-ring. Let the loctite take care of the bolt retention.