Galaxy S6 :: Can't Change Screen Grid Size

In short, after installing the 5.1.1 update, my phone seemed to lag a little on menus and such, so I did a factory reset. Everything was fine, except now after the reset, for some strange reason I can't change the screen grid size in the TouchWiz panel customization menu. The button that says "screen grid" is there, but it's now greyed out and I can't access it. I did some Googling and found that the newest version of TouchWiz (that is stock installed on S6's) is TouchWiz Nature UX 5.0; I checked "TouchWiz Home" app info under my applications manager and it says "Version 4.0".

Could it be that I am running and older version of TouchWiz (because I know the screen grid customization is a feature of the new TouchWiz) -- I don't understand that though, how could a factory reset revert to an older version of TouchWiz than what was stock installed in the first place? I know I could just install a different launcher but I am completely fine with TouchWiz, I just want to be able to change the grid size like I could before the factory reset.

BTW I have a Sprint 32GB S6 with everything unaltered -- non-rooted and everything stock. I would post a screenshot but I can't figure out how to upload an image from file.