Yes, I would say your right on everything. FYI: Aankomstpassage is the arrivals hall.
There is a third source of postcodes, but that is a bit advanced, it is the BAG viewer. That is the official source for every building in the Netherlands (BAG is Base Administration for Buildings). Most shops will be in the Vertrekpassage (departures hall) with postcode 1118 AP, but there are also a few other addresses (in Openstreetmap) like the McDonalds at Vertrekpassage 278 postcode 1118 AW. That is not in the BAG.
Geef ons je mening. Heb je ideeën waarmee we de site kunnen verbeteren? Deel het met ons!