Hill Assist TECH question

This is a question for anyone who works with (or has knowledge of) the software for the Hill start assist driver aid on the new Ford Fiesta (later 2017 model).

It’s not a question about how to use to use it or turn it on or off etc. I know how to use it, I know what it does and I know how to turn it on and off manually. 

I would like to know what the criteria is for the Hill start assist to automatically disable itself due to driver error ?

I am a driving Instructor and as a ‘quirk’ of the job, my car will inverianle suffer with the odd stall. Sometimes after a stall, the Hill start assist will be disabled and sometimes it won’t. Also, sometimes the tick box in the menu will simply be unticked, and other times the option will be ‘shaded out’ ? (Therefore showing that a different ‘causes f stall, creates a different software option to disable the Hill assist function).

So, could someone tell me what driver error causes what disablement option ? (ie, a stall through bringing the clutch up too quick = ***** , a stall for being in the wrong gear = ****) so that I can monitor and eliminate these faults. 

*oh and on a side note , why isn’t there a dash icon to say if it’s on or off !! Like there is for auto restart ??