Gotta be at least 60 degrees at a time, or you can't reset the wrench to the next position.

Open end wrenches for external hex bolts are usually cocked 15 degrees so you can do as little as a 30 degree swing. Flipping the wrench switches the head from 15-degree left, to 15-degree right. Adding the 30 degree swing gives you a total of 60 degrees, which mean you can grab the next face on the bolt.

But Allen wrenches don't have such a feature. You need at least a 60-degree rotation before you can reset the wrench.