The Ed does appear to be in a different garden to the rest of us.
His recent newsletter ( perhaps that really should read Newslater) has directed our attention to Videos on YouTube where, advising how to reply to postings, he has said:-
"As this is my question I am going to thank all the contributors. Leaving an answer on your own question is the best way to say thanks to other users"
Could you be referring to the method used by banks for the allocation of account numbers, where the last number is a 'check digit', which should eliminate people transposing numbers when inputting their account details anywhere: