I don't know what information I can get from that anecdote. I am a trader not a retail investor that holds 9 months. I want to be green at the end of the month, every month. I want to make 30+% per year every year regardless of market up or down. Only way I know to do this is high frequency, and that means commissions are a decent fraction.
Are you saying that it is possible to do all that, while only paying 3% of gross? That sounds amazing. Please tell us a bit about your trading, if you don't mind.