I don't think the slow down will affect this tower. The market is slowing down, no doubt, but its enough for the current pipeline of towers to be successful without waiting "x" amount of time for things to pick up.
Granted the number of units in contract gets reduced dramatically once you get to 20 mil +, but there is still enough activity to warrant this tower as not all of the units will be stupidly expensive in terms of 50 million plus. So I doubt any sort of capping. Why would they? Build it, sell the units that can sell, and the high profit units such as those that rival 220 CPS or 432 Park, wait until the market corrects itself or the demand picks up. If anything, the real risk question is how long will they have to wait until they sell all of those top units. As we've seen with One57 or 432 Park, it takes time through the lifecycle of the construction process. Can't be acute, which is expected with such a high profile tower.
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Credit for all: TRD