If I'm not mistaken, the agreement is for the island of Ireland but since NI and Great Britain don't want custom borders, the rest of the UK have to align the rules to NI(or more accurately the island of Ireland).
It has an undeniable logic, but maybe:
@Adebesi
Didn't you forward an idea that there could be trade border checks between NI and the UK but only for the trade of EU goods?
Do these developments not suggest that will be the case?
This, something like this, something we haven't figured out yet, or something that hasn't been agreed, or even discussed yet.
Despite everyone's kind advice I still have the feeling I haven't learned a right lot so far.