Here are a couple of calculators so you can see how your Non-Spin Offset and Performance Factor are currently calculated.
You will need several of your boat measurements to run the calculators, so have those on hand. To be consistent with the data we have on file for your boat, you can print out your certificate before you use the spreadsheets.
Open the spreadsheet. The first row shows the column headings, which generally match the data you will need to enter in. Type over an old row (except for the first two rows), or add a new row, entering the data requested into each column.