This puts unnecessary load on the CM environment as each added computers counts as a query, instead of just adding all the devices to a query in the collection.
The query should look like:
select SMS_R_SYSTEM.ResourceID,SMS_R_SYSTEM.ResourceType,SMS_R_SYSTEM.Name,SMS_R_SYSTEM.SMSUniqueIdentifier,SMS_R_SYSTEM.ResourceDomainORWorkgroup,SMS_R_SYSTEM.Client from SMS_R_System where SMS_R_System.Name in ('Client01','Client02')