Geoff/Aser,
The group you need to engage in this discussion is are the former members of the Helicopter Airworthiness Study Group (HASG) who sponsored the Limit Override Workshop conference at Vergiate in November 2001. Nick Lappos gave the Keynote speech and at least one of your own Test Pilots (Nigel) was there.
The concept of limit override was to "Sacrifice the engine to save the aircraft" not to have something that "Sacrificed the aircraft to save the engine". As I remember it, the concept was one of a 'blow-away switch" that could be used in emergencies. This might be more pertinent to the AW139 where there is no access to 30 second power limits.
There were also discussions about twin-engine operations where the OEI limits would not be exceeded but the twin-engine limits would (a gearbox limit); not sure whether such limits are employed as it would require communication/protocols between the FADEC of both engines.
I must say I agree with Geoff when it comes to procedures; best not to double guess the system, much better to comply with the manual and seek clarification of the function of the 'TL' from Agusta.
If the 'TL' is related only to OEI operations (hence the discussion on training), you appear to be in danger of leaving one tool out of your toolbox in an emergency.
Jim