Federal mandate calls for 350 more units to be built on the site of the Columbus Homes, which is now vacant.
The town's redevelopment plan also calls for 1,800 new rental units to rise near the rail station.
It first called for 4,000 units, a number that was reduced in 1992 to 2,600 units.
The current plan calls for 624 residential units as well as 42,500 square feet of retail space.
Plans call for 3.5 million square feet of office and retail space, and 640 residential units.
All parties have now agreed to a plan that calls for 709 subsidized units.
The original plans called for more than 160 units.
The site-preparation costs would come to about $35,000 a unit in a plan that calls for 10,000 units.
A major car accident or even a maternity emergency could call for 18 or more units of blood, she said.
His agreement with the town called for 40 one-bedroom units to be created in the old school building.
