There are two Notes with a reverse mortgage loan (just as there are two Deeds of Trust or Mortgages).  The first Note is to the lender, and the second is to HUD.  The only amounts that would begin to accrue to the Second Note would be for any amount that HUD was required to advance on the borrower's behalf.  This could include but is not limited to any taxes or insurance HUD needed to advance that the borrower did not pay or any fees accrued because of servicing the loan if the borrower defaulted after the loan was assigned HUD, etc.