Townhouse "sold off plans"

This is a good example of how to create value and minimize expenses. Sold for $15.3 million 4 years ago so looks like a pretty good return given the market. A very special property for someone who will take advantage of approvals but customize as they see fit. marketed in 2017 for $35 million plus $15 million in renovation costs. I am thinking the 22,000 sf includes the air rights, basement and possibly the double height living room if divided.

What I still don't get are these as renovated asking prices for townhouses that also have approved plans. Are these just teasers? Why would someone hire the seller's builder?

https://nypost.com/2017/02/24/this-new-mansion-is-slated-to-be-the-citys-largest/

So 17000 sq ft ex below ground space. Seems fair for a development site designed by Maya Lin and with Landmark approvals - which would have taken the new owner at least 1 year. Another $15mm for construction and carry etc and the owner is around $2k per sq ft ex outdoor space typically expected with townhouse and not included in the square footage. It is not a townhouse area, if it were to be in prime townhouse areas, it may have traded higher. It does show that the ultra luxury market has come down a lot.

Between cost to carry, hard costs and sales costs I'm not sure how good a return on investment this was.

What happens to AV when property is converted? Does City start all over again and base new AV on cost and/or sales price? 6% of $20 million = $1.2 million AV which is pretty much where AV is now but tax rate is double so maybe new taxes are around $18,000 per month or $220,000 per year? Less than $1 psf per month but still, thats a big nut.

30, Would yon call this location better than 73 Washington Place or worse ignoring the size and features of the property?

While I personally would probably pick 73 Washington, I think the market probably prefers 11 Hubert.
Won't the AV be based on the value of the finished house? So 6% of $35 million?
$2.1 million. At tax rate of 20.385% that would be $428k/yr almost $36k/mo???

30, I would not have thought that 11 Hubert is preferred but waterfront area in northern Tribeca has changed a lot. I would be hands down 73 Washington and would have paid at least 25% premium for unfinished space over Hubert.

On taxes, my understanding is that it will be based on the average of the other 1-3 family houses sold (city does not differentiate based on the condition but I may be wrong) per ft in Tribeca (with square footage calculated as DOF/B records. If you contest the city assigned value, you can use your own purchase and reno cost. $36k per month adjusted for square footage will be $2 per sq ft which is not far off from various new development taxes.

The City will obviously know the purchase price of the property but not necessarily the renovation costs unless the building permit includes the full value. I think in practice, the building permits would show a much lower cost figure but maybe I am mistaken. I do know that this used to be common practice.

Compare 11 Hubert to 443 Greenwich St (which arguably could be the hottest address in recent memory).