I still think the word 'provision' is not specific enough to imply that it must be replanned in flight.
I cant believe it ahs come to the dictionary defintion of provision but here we go.
From an Oxford Dictionary. Provision: providing for the immediate occasion only, of a stop gap kind, temporary,
subject to revision.
Again the law as according to AIP (using myknowledge of the English language) is quite specific inusing the word provision.