I140 EAD under compelling circumstances - At what point 140 EAD invalidates non-immigrant status?

[DodgeRam]

I recently got my h1b extension denied, my company is pursuing filing Nunc Pro Tunc in premium. in a meantime, I wanted to know my options with i140 EAD under compelling circumstances (Note: I do have compelling medical circumstances).

My question is --  If my H1B extension gets approved and i decide to not use i140 EAD for employment purpose, do i lose my non-immigrant status? At what point 140 EAD invalidates non-immigrant status? Upon approval or once i start using it?

I read through many analysis of i140 EAD under compelling circumstances but couldn't get this clarified.

 

Please advise.