My CRP doesn't know what you lot are talking about. Or I don't, or both.
My CRP has a Mach No arrow in one of the windows, but I never went fast enough to need it. I couldn't find anything about OAT associated with that. Maybe mine's the older, slower, lower CRP?
My Jeppie calculator does all sorts of clever things, but you have to know how to drive them, and I never cracked that bit.