Thats how it usually works though. The developers propose 15-20% higher than they think they can get that way during the community review process when the neighbors demand that the height gets reduced they can knock 15-20% off and end up around where they need to be. Winthrop center was proposed initially at over 1000 ft and south station tower had a few hundred foot tall spire on its roof. The residential at hub on causeway was proposed at 600 something feet and the verizon tower had a spire at one point. One bromfield hasnt been built yet but the latest proposal is damn near half as tall as the first proposal. The two I can think of that actually got taller as time went on are millennium (filenes tower) and 1 dalton which had an early placeholder around the height of the r2d2 building, but these are exceptions to the rule.