Chasing the insulin with carbs? do you mean the other way around?Chasing the insulin with carbs puts those carbs into the muscles as glycogen = More fuel ; endurance strength / more pumped muscles.
Did you take the T4 the day of the blood work (Before the blood draw)? This will raise the lab result around 15-20%. So it's a good idea to skip that day.
Wouldnt the excess carbs just result in fat gain?