To answer your question, there would be no change

To answer your question, there would be no change if all your shares were purchased at the same price and sold at some later date. The problem occurs (from my perspective) when you buy low, continue to purchase shares as the stock goes up and then sell some of the shares. In that case, your cost basis would be the first shares purchased (first in first out). To me this is a real slight of the hand change to grab a lot of revenue.