Mrs. Eddy conveyed her real estate to the church authorities with the provision that there be absolutely no changes in the Manual.

This is impossible to dispute --- that there have been changes --- whereas, it is falsely claimed that the estoppel question is open to interpretation.

There were two protections: (1) the estoppel clauses and (2) no Manual revisions, meaning changes.

The latter protection makes the courts in charge via the 13 Deeds of Trust, just as much as the former.