If you include Social Security and Medicare tax withholding to the effective tax rate on $60K, you’ll get to 30%. One of the reasons Buffett’s effective “tax rate” is relatively low is because only part of it is taken as salary. He invests heavily in municipal bonds (state and federal tax-free), maximizes his qualified retirement plans, exercises stock options at favorable rates, and uses annuities to defer taxes on non-qualified income. Anyone making $60K can do many of these things, too.
I've run the numbers at it would be 25%. But you are right, that is probably what he meant. And you are right, Buffett knows how to invest his money -- which is all the difference.