EASA AMC 20-6 - Established aeroplane status before the ETOPS Entry Point

EASA AMC 20-6 defines the surveillance to be implemented in flight and in particular before the ETOPS Entry Point, which includes the established aeroplane status, without further details.

In addition, Aircraft manufacturers establishe diversion decision making procedures for ETOPS flights.

Can this diversion decision making also be applied to entering the ETOPS zone, or should the technical status criteria of the aircraft be more restrictive before entering the ETOPS zone than once in this zone?

Thank you for your clarification.