I agree, a better calculator is needed but I would say the spread is correct other than the average house actually is can vary a great amount. The 360k house in BV is likely 4 bed, 3 bath, 2 car garage with a minimum of 2,000 sq-ft and a basement.
I just looked up Alexandria, VA, one of the better school districts in DC, and the average home price is $500k but my buddy paid $625k for a 3 bd/2ba split level, no basement, no garage. It was a flip job so the kitchen and baths are nicely redone but it still looks like a $150k house in Old OP.