Yes, the Notice of Mistake is not a counter offer, rather non acceptance. It doesn't ASK for proof of claim as counter offer, it states facts that cannot be rebutted and, by AUTHORITY, settles and closes.
Printed copy · Anthology Volume 9, page 424Printed copy from The Tender For Law Anthology, Volume 9, page 424 (printed 13 June 2014). Added by this site; not part of the Facebook export.