The impetus behind the AVI is to "value at market rate" -- the idea is that by updating the valuations, they'll eliminate the unintentional tax break/overcharge some people were getting.
A funny thing about gmaps and Philly -- Philly's changing so fast that that 'dump' is probably a new renovation by now. The building I live in now still appears on Gmaps in its unrenovated state.
Regardless of whether it remains a dump or doesn't, the reported valuation of the dump for 2014, according to the linked application, is $92k, while the nice place has a valuation over $5m. So the dump is paying over 1% while the mansion is paying .2%
A funny thing about gmaps and Philly -- Philly's changing so fast that that 'dump' is probably a new renovation by now. The building I live in now still appears on Gmaps in its unrenovated state.