So I mis-remembered the shall/should difference
...
I still maintain my point that the 'should' implies obligation
Then I shall suggest that we should get this thread out of the weeds (mods may suggest that we must). And no, there may not be a very high probability that we will--in either the probabilistic or financial lexica.
And since we're down here, I present to you the IETF best practices for requirement levels.