I like the way the tabs on the bottom are on the one pictured in the ebay add, I don't know how the housing on my 07 is set up but I'm sure going to check this morning. I don't want to end up with the same problem the OP has with his setup.

 

They all seem to warp to some degree. I'm surprised that there is not an aftermarket metal copy of the factory piece. I don't mean a billet anodized aluminum $299 piece, I mean a $79 stamped or cast made in china piece.

OR...

How about an aftermarket add on clip for that spot that always warps. Seems like an easy $29 for one of the many companies making ford stuff. They would sell a million of them.