Mc version: 1.12.2
Forge version: 14.23.1.2561
Mod version: 3.0.11
Issue: When sieving gravel in the heavy sieve it takes one click to get items even if configs say takes 24 or 6 clicks

The option you're looking at is The maximum amount of clicks per second on a heavy sieve. Clicks above this will be ignored.. That's not the speed at which it sieves. The speed is fixed, and the reason it's only taking one click is because you're probably in Creative Mode.