That's true (She was on Hannity & C tonight - Must be a slow day so they needed a 'Model'). Nonetheless, the increase in assessed value of 370,000 and an increase of some 20,000 in taxes is excessive and would appear discriminatory to owners of multi-family units - Not unusual in NYC.
Let's assume that they convert the brownstone to a four-family building, and each of the four units is occupied by a family with two kids (regardless of whether or not the owners live there). The cost of public education in New York City averages something like $10,000 per child, which means the $23,000 in taxes would barely pay 25% of the cost of educating the kids in the building. And we haven't even discussed the REST of New York City's public-service bureaucracy.
New York City is going through some very interesting times right now. The residents of the city used to pay property taxes that were much lower than their suburban counterparts, due to the substantial property tax revenues collected on commercial buildings in the city. But every time a major employer threatens to pack up and leave the city, the government throws all kinds of tax abatements and other incentives their way in an attempt to keep them. Someone has to make up for that lost revenue, and to be honest with you I really don't have a problem passing the tax burden to the people who live in the damn city.