Hi June Billie. I am not sure but I wonder if the "D9P block" measurement includes 4 units sewn together. I am NOT hip on all the latest so I do mine and lay each individual unit as a block. I am fussy with laying out my scrappy quilts. I cut 6.5" square and my single block is 9" unfinished. I wish you the best of luck. This math is just driving me up a wall. Hang in there !! Here are some of the blocks I am working on. Thinking of setting them on point. I don't know if anybody has done that before.