I have seen my score become more consistent since I starting wearing a jacket. I shoot over my arm I consistently dropped 3-5 shots a match from flexing my left arm or right shoulder as the shot is released. The jacket helps to stabilize my upper body and give a bit more stability.
I take my jacket off between lanes to let my body breath. I also drink plenty of water and eat and drink protein snacks during the match. That help offset being hot in the jacket.