I want to do a what if analysis (matrix) in excel using NPV as the main and use sales and discount rate to simulate. I have no problems with the discount rate as my base case will be 10% and then i'll have a range of e.g 5%-30%, but my problem starts with sales. My NPV is calculated using cashflow for 10y, but the forecasted sales during these periods from time 0-10 differs, and therefore I cannot use a constant e.g 20% annual growth sales. I could calculate each years sales growth manually and the take the mean, but to me this will give me a very approximate estimate which isn't true to the real value. If I use the same sales % for all years it won't consider the fact that the growth lies in the last 5 years and I believe i'll get an incorrect NPV. Is there a way when doing a what if matrix to account for a non constant rate and not use a constant? Or is this not possible in a what if analysis matrix?