That was exactly my point.
there is a misconception that the RNP value changing to lower than 1 is an indication of ‘on-approach’. In fact the logic would be in ‘on-approach’ before the RNP displayed changes, we just don’t know when!
i find it odd there’s no indication to the crew as to which logic the FMC is using, it does make quite a difference as to how certain situations would play out.