You're better off using a chimney charcoal starter to light the new coals then taking the center section off to reload. That way, there is no question about using an outside heat source. You will probably not have the meat off of the heat as long also.
If you want to do it the way you posted, ask the contest rep at the cook's meeting for an answer. Ask at every contest because you may get different answers depending on the rep.
Good luck, Benny