So the number of Shares Outstanding is NOT a BIG concern. Investing the same amount of CASH each time is good enough. We only Average Down if the stock price dropped due to Market Conditions or Market Maker Manipulation. It's very common for a stock to fluctuate in price for no REAL reason. People sell stocks for MANY MANY reasons, such as, selling a stock for a tax-loss or selling because you need the cash.
MOST Investors buy and sell stocks based on their emotions.
Averaging Down can be very profitable IF you do it with a GOOD Low Priced Stock that is already considered Under-Valued. Do NOT Average Down more than 2 times. Plus, we never like to put a lot of money into one stock. OR we might wait to see if we can buy the stock at a cheaper price. We usually do NOT Average Down if the Company starts to Lose Money.