It'll probably be much more than 1 hour before it's ready to go into the cooler.
For the record, there's a number of approaches to dealing with the stall; 1. Wrap the brisket in foil at around 150 degrees. 2. Crank up the chamber temp. 3. Combination of 1&2. 4. Just crack open a beer and ride it out.
Also, cooking at a higher temp right from the start (275ish or even higher) will minimize the stall.