Property reassessment

Received a reassessment notice from the county in the mail today.
From last year’s property tax bill, the house had an appraised value of $227100 and an assessment of $9080 (4%).
The reassessment notice says the house now has an appraised value of $243000 (pretty much the original purchase price) and an assessment of $9720. If the millage rate stays the same as last year, this means my property taxes will probably go up about $160 this year (maybe a little less depending on how many tax credits show up on the bill).
Zillow.com’s estimate of my house’s value was $216000 last week, and jumped up to $227800 this week.

I have no idea what kind of strange voodoo or mathemagical incantations Zillow.com uses to derive their real estate values, but it sure does look strange.
Good thing I’m not planning on moving anytime soon.