That's a tricky question. The selling price doesn't correlate with the assessed value of properties. Typically condos and homes sell for above their assessed value, but properties also sell for below their assessed value.
The important figure is the Sale Price to List Price ratio. In 2012, the Average Sale to List Price in the South End is 98%. That means that condos are selling at 98% of Asking Price. That amount doesn't reflect price reductions, but 98% is a very healthy number, at least for sellers!