I wouldn't assume that it will be done too early.
you may need 200 to be tender and it may take several more hours
( in my very very limited experience ).
Brothers, correct me if i'm wrong.
i'm only talkin' to ease this man's pain.
also...I was advised yesterday by a brethren that you can put that brisket in the cooler ( when it's done) and, if properly insulated, it can wait there for several hours till dinner time...when it will come out still hot and juicy.