Because I plan on redoing the bottom of the Platinum grill with Durawood, and I thought that would match better with the gray shelves. Eventually I would like to have platinum shelves on both though. I also plan on using a wire rack bottom on the Silver C. These are the two bottoms I have the the inside contents of. I just have not come up with the money to buy the front and back rails I need for the 2 grills. I am sure these 2 bottoms look familiar to you all.