A couple of glitches were discovered in the "Points" worksheet of the "SECTPROP.xls" workbook. There was a range/column of cells in the calculations, M29 through M38 which had an invalid cell reference (#REF!) in each of them. This problem would have shown up for points #26 through #35. Also, the series data to draw the plot omitted the 'yo' coordinate for a group of points, thus even if the other problem had not existed, all of the points would not have shown up in the plot. The necessary corrections have been made, and the workbook is now version 2.4.