Service variability is the degree of actual variability from the service provider over the variability required by the tenants for the service. With a growing number of tenants, the likelihood of facing more diverse tenants’ requirements will increase. We conducted a study of how choices regarding service architecture affect service variability and the cost of supporting a service. We identified positive and negative impacts of service architectural choices on service variability. We conducted workshops with industry service providers to validate our choices and their experiences on multi-tenant engineering. Knowledge of this information can assist participants with making more informed decisions regarding multi-tenant engineering.