Man Steve, that SUCKS! I would be very frustrated (you probably are).
If flex is the culprit then we should be seeing servos with broken cases or ears broken off too.
I think the flex in the tray is as much about the material it's made of as it's not surrounding the servo. When I first put my servo in (Air 258, hope it lasts...) it flexed the tray a lot before I adjusted the EPA's. I was lucky to notice the excess spring length right away.