As context: aviators have at least five references that (in reasonably-populated and infrastructure-supported areas) they can usually use:

* GNSS

* compass

* VOR (ground radio beacons emitting a patterned signal to point to where the beacon is)

* Visual landmarks

* Asking air traffic control where radar spots them to be

The meat of this planned change, IIUC, is that maps that have to change to account for shifts in magnetic north over time will now be static, and instead additional offsets to correct the true north / magnetic north error will need to be factored in when an aviator uses one of their five common navigational aids. This seems like a reasonable place to put the costs.