Blacksheep -
The AMM is ALWAYS the overriding authority over an engine manual.
For example, an engine power assurance check is always done to the AMM and not the engine MM if there is data for such in both manuals.
In fact, in this example, if there is data in the AFM, it even overrides the AMM.
The only document that can override the AMM/AFM is an AD.
Its one of those quirky things.
K