Actually, 10x has absolutely nothing to do with how many times it's sifted. It refers to the fineness of grind. 12x is the finest, and I think 4x is the coarsest
I don't ever see Domino brand, except for granulated sugar. Is it in a bag or a box? If it's a box maybe that's why, I only look at the 2# bags.
I have used GV (don't like it), Food Lion, and Dixie Crystals (when I can find it, it seems to always be sold out).