Hi Vitali, I did the spreadsheet modification a long time ago but my formula for the PC multiplication factor is as follows: 1+ (date1-date0)/365 * %inc/100 where date0 is the initial date, date1 is the next date, and %inc would be 20 in your case. My date is in format 2/24/20 and you must define that as a date in Excel In other words if you subtract two dates in excel it's equal to the number of days difference. Adam