A&W used two 3oz patties, and when McDonald's gave the "third pounder" a try they used one 6oz patty. Both of these are 3/8lb, which is 12% more than 1/3lb!
Important to note that that is the weight before cooking, a frozen patty will lose a lot of water weight in the cooking process, so what you end up getting is not a full 6oz.
Sure, but that applies equally to the quarter pounder, which is 4oz before cookie.