The point he's making is: If OP bought his 1000BTC for $150 each, then did this buy/sell business, he wouldn't be in profit, he would be mitigating his losses. That's just how I interpreted it (the post I made earlier shows how this was not the case, however the theory is still valid)
I understood his point, I just don't understood why he/you for some reason think it's natural to include previous trades here. If you want to play that game, why not include every trade he's done since birth while you're at it, to figure out if he's made a total "profit" or not? 