more info, padi dry suit knowledge review question 4.
How do attain positive buoyancy at the surface, attain and maintain neutral buotancy underwater, and prevent dry suit squeeze when dry suit diving?
At the surface, add air to BCD, not dry suit. Underwater, if you’re wearing a shell dry suit add air to the dry suit to adjust for neutral buoyancy. Underwater, if you are wearing a neoprene dry suit or if you are wearing a dry suit for tec diving, add air to your buoyancy compensator to adjust for neutral buoyancy. Add a little air to your dry suit on descent to prevent dry suit squeeze.
This is out of the "08" instructor manual