This is incorrect.
The reason he gets away with this rhetoric is because 35% of the profit is already being given to the govt. before they cut his check. Add in his 15% and you get a 50% tax rate. So, no - your tax rate isn't higher.
You can play stupid number games like this all day. Just tax corp profits at 50% - eliminate cap gains for the individual and what do you get? The govt gets the same amount. Buffet gets the same amount after tax, but his "total federal tax rate" is now like 2%. Yet there isn't a single extra dollar in his pocket.
That's fine, but he is using faulty rhetoric to make a point. If he wants to pay more taxes - he can cut the check. I won't argue.