FALMOUTH — The Town Council decided not to allow a zone change that the developers of the proposed Falmouth Center said they need to ensure the viability of the project. Instead, councilors on Monday said they’d prefer to follow a master planning process, while acknowledging that will only be possible if the developers are willing to comply. Developer Jonathan Cohen, who purchased the Falmouth Shopping Center this past spring along with Joseph Soley, could not be reached before deadline to comment on the council action. But in prior interviews and public meetings, Cohen has said the zone change from Business Professional to Village Center-1 is necessary to accommodate the Seacoast United athletic organization, which wants to build two outdoor turf fields and an indoor facility. Seacoast United is the only announced tenant for Falmouth Center, which Cohen has said would be phased in over several years.