No real probs except there are issues with WAC charts and true positions at close zooms.
My first instinct is to say: that's because the WACs are of poor quality! Have a look at Strathalbyn. Yeah, it's right on where two WACs were stitched together (Port Augusta and Adelaide) and it's clear it is marked in different locations on each map. Although usually close, I would take the true position of anything on a WAC with a pinch of salt... (something you are unlikely to notice when dead reckoning.)
That said: if you can find multiple point that are out of place in the same area, especially if you see roads not match up, there could be an issue with the geocoding of an individual map, so do let us know!
Bas.