Good questions!
Loan Accounting gives us a clue...
Lawful Money Full Discharge Instrument-ACCOUNTING does too...
But we, as Beneficiaries, do not need to know that... we specify the WHAT ("I authorize payment"), the Trustee's duty is to know and do the HOW ("discharge upon payment").
IMO, all they really need is our signature across the face of the "bill".
But, to SHOW WE HAVE ELABORATED, this STAMP is recommended (K.I.S.S.).
And isn't every corporation really acting as an Agent of the Treasury/Trustee anyways, as a sub-corp of the US Corp?
So, as agents of the principal/trustee, they should know HOW to handle getting a credit from the trustee, right?
So, let's hold them accountable, and if they fail to perform, that is outside the scope of their principal/agent agreement, and then can be held liable. This is where a CLAIM comes into play in a Court of Record, for harm to a man.
See this Conditional Acceptance for BILL that has worked for me in the past in that regard... with several entities...
PM me for private details...