AVM (Automatic Valuation Methodes) use different algorithms to arrive at an average price. The asking price may depend on when the sellers purchased the property (did they buy during the real estate "bubble"), the upgrades installed, recent comps, etc. The AVMs could be "spot on" in a neighborhood of "cookie cutter" homes, but way off where the homes are dissimilar. (Frame versus brick, etc.)
If you're interested in purchasing a home, then you should use an agent or broker who has the ABR, i.e. the Accredited Buyers Representative designation. Having this certification means that the holder has not only taken the classes, but additionally has the transaction exerience in representing buyers.
Please let me know if I may be of further profesional assistance - Bob Lepelletier, REALTOR, GRI, ABR & SFR - Broker - Associate - Keller Williams Realty - Alexandria/Kingstowne Office 703-310-7880 and bob at bobtherealtor dot pro.