Dear MB:

You wrote:
> Mr is a contraction of Mister.
> Rev. is an abbreviation of Reverend whereas Revd is a contraction.
>
Perhaps it is taught differently in Commonwealth countries. The American understanding is that in contractions the pronunciation as well as the spelling is contracted (e.g., doesn’t) and in abbreviations the spelling but not the pronunciation is abbreviated (as in Mr.).

Thank you for your input.