Dying hair ashy grey/silver PROFESSIONALLY

I’m getting my hair dyed PROFESSIONALLY. Not at home. My last post everybody assumed I was doing it by myself. No. However, I am still skeptical that it could come out orange even with a professional! Do you think it’s inevitable it’ll come out orange or is that the slight risk one takes? I mean they specialize in this but I still hear horror stories but I also really want that ash grey/silver look!