To be honest, when smoking a whole packer brisket by the time your flat is right the point may be technically overcooked and a little soft. So I balance the two and get the flat close enough but try not to go to far on the point. I’m really not supper picky but some people separate the point and flat. They cook the flat as brisket and when the point gets close they cube it up and make burnt ends. I think that is just silly and always keep the packer whole. Just remember that technically you are smoking two separate muscles that are joined together and have different structure and fat content.
Also never leave a probe in the point, even though it’s the thickest part, because it will finish faster and it’s very easy to have the tip of the probe in the big fat seam. Always watch that flat temp and probe feel. Check the point to for reference but really cook the whole packer for the flat not the point.
Btw, the point is my favorite plated, I’ll eat the flat but leave most of that for others.