When reassembly plastic pieces that are held together with self-tapping or sheet metal type screws, it is very easy to cut a new thread in the plastic boss and thereby weaken the hole. You can even strip out the hole if you are not careful.
The right way to reinstall the screw is to turn it backwards until you feel it drop into the original thread that the screw cut into the plastic at the factory. The screw should then spin in with little effort and tighten nicely. If you feel any resistance, you may have missed it. Do it again.
BING, BING, BING, BING!!! We have a WINNER!
Not sure what you've won, old boy, but that is GOLDEN!
I actually teach this in my classes before I let anyone touch a screwdriver, OR my components!