lol, I work from home...my dog may ridicule me, but I think I can handle that
no need for the rubber mats, the chassis is grounded with that screw that holds the connector down in the bottom left. It just seems that the HEP ballasts are a little more stable when grounded using the grounding pin on the power connection side than they are just having the metal body grounded to the chassis. I've only seen the problem once, but the result was ballast issues similar to yours...it can't hurt to do this, and you will already have it cracked open, so think of it as more preventative than anything else.