MOUNTAIN VIEW — The push and pull over how many residences should be included in the Mountain View development slated to contain a huge new Google campus has received a prod toward a higher number.

City staff reviewed an October draft proposal for 9,850 housing units and concluded in a memo to council last week that even with a new Highway 101 off-ramp, the North Bayshore development could only support 1,500 to 3,000 units.

But on Friday, Google, which is preparing to build a massive new “Charleston East” campus in North Bayshore, sent a letter to the city saying the company wanted the 8,950 units built.

“We are concerned that if residential development is limited to 3,000 new dwelling units for a particular period of time, the required residential density will not be developed that is needed to justify and support transit improvements and (a) successful neighborhood serving retail in the area,” Google real estate director John Igoe wrote in the letter posted to LinkedIn by Adina Levin of Friends of Caltrain.

“It is the density of the 9,850 residential units with the retail and office uses that will justify and support the investment in transit improvements, bike and pedestrian connections, habitat improvements and new retail uses,” the letter said.

Who would develop and pay for North Bayshore housing has not been determined. Council member Margaret Abe-Koga told this news organization last week that Google has discussed building 2,500 to 3,000 units, but “there’s no indication they would do the 10,000.”

Under the October draft plan, small “micro-unit/studios” were to make up 40 percent of the housing, followed by 30 percent 1-bedroom units, 20 percent 2-bedroom units and 10 percent 3-bedroom units. Twenty percent of units were to be considered “affordable.”

The same mix would apply under the staff proposal for 1,500 to 3,000 units, Abe-Koga said. Staff noted that their recommendation did not preclude council from approving all 9,850 units. The matter is to come before council Tuesday but no final vote is expected.