FSD I just typed out a long reply and I submitted it and the stupid site crashed on me…Anyways I see your point. I “think” the diversity of Poway housing factors into it more…
My guess for this particular case (Dec yoy) is due to the high ends of the sample. December of 06, the top 5 sales were 1.18M, 1.2M 1.2M 1.74M and 2.075M while December or 05 top 5 sales were 920k, 940k 985k 1.085M 1.71M.
Your right these problems should scale over every zip but I don’t believe most zips have the diversity that Poway does.