Boston’s biggest experiment with “co-living” is looking a bit more companionable.

National Development wants to add 34 three- and four-bedroom units to its 7INK by Ollie tower at 217 Albany St. in South End, while eliminating 113 studio apartments.

The 139,900-square-foot project approved last summer is billed as an all-inclusive housing option featuring furnished apartments with convertible furniture, housekeeping service, events planned by a live-in community manager and hotel-style amenities.

Under the original plans approved last year, the majority of units would have been 500-square-foot studios.

In a filing with the Boston Planning and Development Agency, Newton-based National Development said it’s proposing the changes based upon market conditions and results from other co-living developments. The target demographic of 25- to 40-year-old renters is gravitating toward multi-bedroom units because of lower costs, according to the firm.

The changes would reduce the overall unit total from 353 to 327, but the size of the 14-story tower would remain unchanged.