Does anybody know any details re:new floors addition?

Looks like usually building grows approx. 1 floor per week, so they might get from 15 to 40th floor in about 6-7 months, which is by March-April 2014... So what if they done building by March - there's not enough time to finish in 2-3 months anyways, right? You think it'll take about 5 months...

Tentative occupancy date for 40-45th floors of West Bldg is listed as May 2014, and for 40-50th floors of East Bldg is June 2015. Does it look realistic considering that for now West has about 15 floors and East has about 4-5 floors? Thank you!