I'm no brisket pro, but as with butts, I think it's all about the look, not necessarily the temp. I've done brisket before without foiliing at ALL and it turned out great. If the bark is where you want it, foil it to keep it out of the smoke.
TIP: Put some beef broth in with the foil when you DO wrap. This will help keep it hydrated and give it something to steam.
Basically, if the flat looks good to you, this is as good a time as any to seperate the point and put in a hotter part of the smoker (if you have one). If not.....let it ride.
Remember.....the flat is done when it's tender and not before. 182 is still probably tough. The probe should go in with no resistance. THEN and only then is it done. At this point, forget the temps. Worry about probe tenderness. Personally.....I'd probably let the whole thing go until the flat was probe tender. THEN seperate the point and put it back on and keep the flat wrapped up tight and hold in a warm oven or a cooler until the burnt ends are done.
18.5", 22.5" OTS
Large BGE (chambersuac's)
The Fiery Furnace (chambersuac's)
Big JT's Smokin' BBQ Competition Team