Also price per square foot doesn't reflect lot size. Orinda will, I suspect, have larger lots than Rockridge.
If you wanted to buy a decrepit 600 sq. ft shack on a 10-acre lot in downtown Woodside, a price per square foot metric might seem like it should be <$1M. In reality the property would sell for $10M+ based on the land value, with the shack having negative value because of the cost to tear it down. (Ob. Steve Jobs Woodside reference here.)
You do have to pick something and run with it, I understand that. But price per square foot is pretty bogus because one cannot buy housing by the square foot. You have to buy it per _house_. I think you could make a fair comparison if you went with median 2-bedroom sale price instead.
Price per square foot tends to goes down as square footage goes up.
(For example, a 1700 sq ft home in mountain view will cost you 2 mil. A 3400sq ft one in the same place will cost ~3 mil, not 4 mil).