Thank you all for the help and advice. Yes, it is really the use of formulae in excel that is confusing me. But I am easily confused when it comes to excel.......
Jan, could you let me see a copy of your spreadsheet? I would really like to get to grips with this, as I am trying to keep my brain from freezing up with old age, not to mention the speed of use if I ever get it done. Saab, thank you for the link, but not really what I am looking for.