So I am guessing the main web attachment lace is coming down the vertical posts and then tying off at the top of the base. Then the web base lace is just running the perimeter of the base of the web.
Wilson also uses a separate lace for the fingers and the web spiral. My best hypothesis is that they might be able to use five 40" pieces of lace for the web and fingers rather than three 40" pieces and a 66" piece. It just may simplify production to use fewer lengths of lace.
But the counter to that is that Wilson only uses 3/16" lace, so they need different lengths anyway. But if you gave lacers only 40" pieces, they could cut one in half for the thumb and pinkie and then use 40" for every other section. There would be some waste with the palm lace, mid-finger lace, and web base, but you'd pretty much use up all of the rest of it.