Update property stats at Snohomish county recorder's office

[Kweku Ako-adjei]

Hi all, I have a rental property that I'm putting up for sale in Snohomish county (Edmonds) in Washington state. When I bought the property, it was listed as a 3/1 but its actually a 4/1. When you look at the county records/structure info about the property, it matches my property, but one of the rooms isn't listed as a room. I want to sell the house as a 4/1, and my agent is suggesting that I just go up to the county recorders office and update the info. 

Anyone done this before? Is it that simple? I'm worried about someone coming out to do an inspection and finding other issues and holding up my sale. Any help or info is greatly appreciated.