The Zone VI Compensating Development Timer (if you can ever find one) works quite well within REASONABLE temp boundaries. Once you get too far out, certain
developer ingredients might accelerate or decelerate activity disproportionate to other ingredients. Too hot, typically above 75F, and you might damage the emulsion
itself. Too cold, and depending on the specific developer, some components simply might not have enough energy to jump start them, or at times, even to stay fully
dissolved in solution. A warm water drip line into a big tray, offset with a brick of picnic box "blue ice" can work wonders.