Imagine you invest $100 a month in a certain stock. The stock price dips from $10 to $5, so in two months you have 300 shares. Let's say the price rises back to $10, so those 30 shares are now worth $300. You invested $200.

First month I made an investment that made break-even, second month I made and investment that doubled. I struggle to see where the problem with this is supposed to be.