Very bizarre. I bought a foreclosed condo for $145K in September of last year that had previously sold for $370K in ’05. There were no tax issues – the taxable value is $145K.
Likewise, I had no issues getting a substantial assessment reduction on the condo that I actually live in. I bought the place in a very complicated transaction in which the seller lost an enormous chunk of equity, but the selling price (and thus tax assessment) was based on a much higher price than I ultimately paid. I had no problems getting the assessed value down to my actual cost.