So now I've ripped the center part apart. 8.5 + 8.5 + 15.5 is just never going to add up to 30 inches. So I took the flying geese part off the center and trimmed them down to 8 inches and after putting them on the center block it measures 30 inches exactly. Of course once I have that part fixed I'll have to fix the next part since you're supposed to sew a 15 inch block to a 17 inch block. Right.