WA estimated vehicle registration fees at a dealer

How close can a dealer usually estimate registration fees on a vehicle in WA? I know there are some things they can't know until the state sends the plates, but a lot of it must be fixed.

The first car I bought in WA, I received $14 back.

I just bought another one, and I owed $160 more. This second car was an old beater, so not like some huge excise taxes or luxury fees happening. They are in King county and had my address so the Seattle RTA fee was no secret.

The "estimate" said $100... but apparently it was $260. That is a horrible estimate at best, but my guess is this was some dirty pool to make my out the door price line up on the paperwork. Before I put this guy on blast I wanted to know others experiences.

Honestly, I had stood up to walk out on the deal at $100 more out the door, so this kind of pissess me off that I came in higher due to this crap estimate. Should have kept walking. To me out the door means no more fees anyway, but legally it does say estimate on the paperwork. Thanks.