Do you think it's possible that the building code in AZ
is substantially different than the building code in Florida? The very reason that states have separate licensing requirements is that the building codes differ greatly from state to state and from region to region.
I don't think that you'd want a FL
licensed roofer building the roof of your house in Canada - given that the FL
roofer would probably have very little understanding of snow and its effects (weight, snow dams, icing, drainage, etc . . .)
This isn't limited just to roofers, attorneys, accountants, and doctors to name just a few occupations all need to be licensed in the state they practice. If a CPA in FL
opened an office and certified financial statements of an AZ
company I'm sure that they'd get a visit from the state licensing board.