For the Basic Strategy Player is Playing Two Hands Better Than One

I had a discussion recently with a very lucky basic strategy player who claims that playing two hands all the time improves his odds by 33%.

It has been discussed alot on green chip how playing two hands is good when card counting, but is there any truth that playing two hands will improve a basic strategy player odds.

It appears this lucky player flat bets the same on each of two hands and if things are going good will increase his bet, but he does not adjust his bet amounts that often. He is a pretty good basic strategy player, but I noticed several basic strategy errors such as not hitting 12 vs 3 and doubling 7 vs 9.

I normally post only on green chip, but thought I would ask this question here since I suggested to him to check out BJ21 and he will see the answer here.