Beltomatic safety switch logic

I think I've assembled, fitted and wired up the safety switch correctly.  And I can see the logic in how this switch works, but I don't think my logic matches with the logic of the owners manual.

My logic;
At rest, set the switch lever to touch the pulley so that the switch is open.
As the engine speeds up, the pulley moves away from the switch lever, and in doing so, the microswitch 'makes' (grounds to earth) effectively stopping the engine and letting the pulley slow down and come back out again to the switch, 'breaking' the earth and allowing the engine to start again



Owner manual logic;
At rest there should be a 3mm gap between the switch lever and pulley.  That means the switch is 'made' (earthed).  As the pulley speeds up so it draws away from the switch lever - in this way, as the pulley only ever pulls away from the switch lever, it never actually touches the switch??!!

For a detailed 'official' description (I assume its official, but I dont know where it was published) of how this switch is designed to work take a look at this document on the Manurhin Scooter Interest Group website.  My interpretation of what I read is exactly as I describe in my logic above.... but I just cant see how the switch works in their setup.

The bottom line is that I think the switch lever should be touching the pulley when at rest.  The guide wants a 3mm gap.  What am I not understanding?

I am sure that I have got something wrong - I dont doubt that, and I look forward to someone making it all clear for me