From another site:

[AtlUmpSteve]

I suspect that would be even worse. As it stands now, too many people (coaches and umpires alike) can't reconcile differences in the ASA rule book, the POE's, the umpire manual, and the casebook. Already four documents, and most coaches haven't read even one.

Add further that OBR rules (at least to my knowledge) aren't tweaked annually; and that every tweak or change almost universally creates a conflict in one or more of the four documents.