What "workinonit" said. The stop is designed so that the lever can be by-passed.They are designed to be that way and always have been as far as I know. It's made like that so you can pull the lever to you and hit the stop or push it and go by the stop if you need to lower it more temporarily. My 5 series is similar. I use mine almost every time I have something on the 3 PH. and if I'm not using draft.
Below is of a Late-Model 4020 right hand console control.
Below is of a Early-Model 4020 dash control.