By definition, all bindings must release under the same amount of pressure when set at the same release setting. When set at 12, a DIN 12 binding will require the same amount of torque to release as a DIN 20 binding.
As for turning down your bindings between seasons, I don't bother with it. I did once, and that fall forgot to turn them back up. Fail. Springs are made to be compressed. Look at the springs on your car, they're loaded up constantly, and how long does it take for them to wear out?