This is how they work pretty much anywhere; the locality aims to collect a certain amount in total taxes, and sets a per-$1000 tax rate based on the total value of all taxable property in their jurisdiction.
People think doubling house value doubles property tax, but the bill could go down if double is less than the average increase for the area.
So if they collected $10m last year, and will collect $10.1m this year, it doesn't matter if the houses have tripled in value, you'll pay roughly the same dollar amount.