is a saggy softbox grid a problem?

Last week I purchased a Fotodiox 32x48 foldable softbox. Installation wasn't as difficult as I thought it would be. However I have one problem with it.

No matter how I attach the outer diffusion material and grid, I can't get the grid to not sag. Because is sags, it doesn't make a perfectly shaped grid (seems wavy). Also, it doesn't rest on the white diffusion material (it sags away from it by as much 1-2 inches, worst in the middle).

Is this something that I need to do something about? Is there some kind of trick to get the grid to look as it should?

The 48" octobox I also purchased at the same time does not have this problem. It is nicely taut and has a uniformly grid shape throughout.

Sorry, I dont have an answer for you on the softbox, but how is the quality on the grids themselves? Do they seem like theyll last a bit?

Myself, I don't worry about it. If I wanted perfection, I'd have to be willing to pony of for the Lightools product.