Too Much Brisket??

Im getting a little nervous.  This last week I bought three briskets.  One was around 10 lbs and the other two were around 13 lbs.  I put them on at around 11 last night.  I had some small problems with the smoker early on and didnt get it stable until around midnight.  It is now almost 24 hours later and the internal temps are all over the place.   The smaller brisket is at around 175-180.   The other two larger ones range from 155-165.  Is it possible I put too much beef in the smoker? They all fit fine but I guess if they are too close on their racks, they may take longer to cook.  Please tell me im paranoid and a 24+ hour smoke is normal for these.  I have foiled all three hoping that will help them finish off a little better.

I did a 13 pounder by itself a couple weeks ago and it came out amazing.  I figured since I had nailed my recipe I could make a large quantity.

Thanks in advance for any guidance!

Rico