Answer for Sample spreadsheet

This is quite “complicated” as the formula is is based on geometric mean, and i break down the growth period into 2 parts.
Its generally my estimated number i put in, and the results largely depends on the estimated number i put in. 
Its just a place i keep notes “why” i buy stocks at that time. You can write your own footnotes on your stocks too. Like a journal, so that you can look back at your decisions given the facts at that time, why you buy/sell the stock.