Munk,
Yes, on AS355, A109E, B212, B412, SA365 (all models), S76 (all models), S58T, S61 CDP is IAS based.
How can time possibly have any relationship to ETL? I think you're rather confused or not explaining yourself too well.
tistisnot,
Well said. As you say it all comes down to a proper briefing.
As has already been said all of this applies only to the engine failure case in a multi-engine helicopter. For any other emergency it's pretty much irrelevant.