I was more curious if when using the hill hold (which I don't have) you still have to keep your foot on the brake so the engine stays off or put it in park like on my car before you can take your foot off the brake and keep the engine off? If that's the case and you're either holding the brake on yourself or have it in park then what's the point of having the hill hold at all since hold assist is more than enough in those situations?
Hill hold is standard. Hold Assist is the optional extra.
For Hold Assist - no need to keep your foot on the brake pedal: car remains still and stop-start still works.
If you have the Hold Assist optional extra already, then just flick the switch to turn it off and try it out to see how it behaves? This should revert you to the standard type functionality akin to Hill Hold.
John.