The Taxpayer Advocate paychecks are signed by the same guy who signs the checks for the other IRS units you are dealing with.  Mostly it's a publicity stunt.  But where does it say IRS has to issue a clearance letter?  Isn't Section 6501(d) self-executing, like any other statute of limitations?  I agree with @sjrcpa.  The Form 4810 is like waving a red flag, a tale told by an idiot, full of sound and fury,  signifying nothing.  As Macbeth might have said.