I've never used the tool but immediately a concern came to mind. Let's consider that your/my block is 12 inches finished AND is made up of several smaller portions, e.g. in a miniature carpenter square there are many HST's and regular squares, each one requiring seam allowances. ...it seems to me that the calculator won't account for all the extra fabric needed for seam allowances in the smaller subsets of the that one block. Anybody had experience in checking blocks like that with the calculator in the link?