The number of tenants that subscribe to and pay for a ser-vice, and the cost of the SaaS computing infrastructure are the main factors that drive service profitability. In many application domains tenants' requirements for service vary. Service variability is the degree of the actual variability provided by the service provider over the variability required by the tenants for the service. With growing number of tenants, the likelihood of facing more diverse tenants' requirements increases. The authors conducted a study of how choices regarding service architecture affect service variability and the cost of supporting a service.