Should bonds owned by the Fed be subtracted from the national debt?

This is an interesting question I have discussed before, although I stated it differently - that Fed assets should be subtracted from the national debt.  Wouldn't this possibly lead to hyperinflation?  Yes, but the original question was is there a point when the national debt becomes so big it reaches a crisis point.

Just to be clear, here are the numbers:
1. Debt held by the public (from the Treasury Dept) is currently $10.261 trillion.
2.  U.S. Treasury securities - Notes and bonds, nominal held by the Federal Reserve, is currently $1.570 trillion.
3.  The US GDP is currently $14.582 trillion (per the World Bank).

Using these number, the debt ratio is 59.6%.

If my latest theory is correct, then the maximum sustainable ratio is 165%.  When will the US reach this point?  That is a question for later, but it will be later than my previous projection of 2025, so I will say 2026.

Update 6/19/2011: This is model H-2.  Model H is the theory that debt held by the public, less debt held by the Federal Reserve, cannot exceed 165% of GDP.