The 6% dividends on the paid-in capital are a nit. The "reserve against paid-in capital" was mostly a start-up thing; they did that at the beginning to give the bank some heft. These days the additions to paid-in capital are fairly small amounts, as are the corresponding additions to surplus. Should the Fed ever be closed, the accumulated surplus would be paid to the Treasury, so it's not really accurate to say it's going anywhere else; it's basically going to sit there until it goes to the Treasury. Using profits to pay down Treasury debt is the same thing as rebating the money to the Treasury.
None of that is really the point, though. The usual claim as it comes hot off the Kookburger site is that the Fed is making trillions in interest by holding the national debt, and paying that interest to shadowy foreign bankers. Here's what really happened last year:
(000's) Current Income $33,963,992 Expenses $ 1,971,688 Gross Margin $31,992,304 Assessments $ 188,067 Cost of Currency $ 435,838 Net Income $29,868,372 Dividends $ 409,614 Additions to surplus $ 4,114,865 Rebated to Treasury $25,343,892Pretty slick, huh?