i don't know, if they can actually get it built at 650', then that's pretty par for the course for major office towers in chicago over the past 2 decades.
major office towers since 1993:
- 300 North LaSalle - 785 ft
- Blue Cross Blue Shield - 743 ft
- 111 South Wacker Drive - 681 ft
- Hyatt Center - 679 ft
- UBS Tower - 651 ft
- 155 North Wacker - 638 ft
- 353 North Clark - 624 ft
- Citadel Center - 580 ft
- 1 South Dearborn - 571 ft
- 191 North Wacker Drive - 516 ft
- ABN AMRO Plaza I - 453 ft