To be honest, I always treat UWP Codes with a pinch of salt - most traveller books vary a little, and they all vary from travellermap (which is explicitly recommended as being canon).
My take on it is that in-game the UWP system is written by the scout service but isn't perfect, there are errors and local circumstances can change (populations shift, governments change, extensive industrialisation or a natural disaster can taint the atmosphere, etc).
So, I, as the GM, just pick the source I like as canon for the area of interest (usually based on convenience for me).
The players get whatever's easiest for me to give them as a guide to the area.
If differences crop up, well, that's life, and maybe if appropriate they can earn a little cash on the side 'updating' the scout services data,