OMS, well done for doing the full whack.
I have no concept of the workings of an EA/PTL except (2010-2014) those I dealt with who didn't very much in the way of Maintenance Programme updates (Maintenance Schedule updates) apart from reacting to emergent issues warranting their attention.
I was a rigga from 75-99 and I've worked in airline and MRO quality and continued airworthinesss management since then. As an "aviation" Quality Manager I never touch ISO9001 (QMS is not a legal requirement) so I concentrate on regulations and practices to cut costs in a legal and risk averse fashion.