I agree on the proper procedure, was taught that way BUT I never back off my regulators and have had the same set of small Victor knock offs for years. I even have 2-3 sets of new Victor regulators thinking I will change these out but they just keep working.
And also it is VERY important that the gas never be adjusted above 15 psi. Acetylene becomes very unstable in a free state at any pressures higher than that. That's why your gauge has a red zone after 15. The acetone in the tank is why it can be under more pressure (safely) in the tank.