does separating point/flat significantly change smoke time?

Want to smoke for the 4th - I have an 11 lb brisket and was wondering if I seperate the flat and point - let's assume each are 5.5 lbs for discussion purposes - does that mean I'm smoking for approx 8 hrs or since there is still 11 lbs of meat in the smoker - it is closer to the 1.5 hrs ~ 16 hrs (or perhaps somewhere in between)?

Yes - temperature will govern when done - but I'm just trying to plan my day (or know if I need to get up at 3:00 a.m.!)

thanks all!