Common intermediate storage policy (CIS) is suggested for flexible use of various intermediate storage policies. CIS can accomplish the complete flexible intermediate storage operations to satisfy more frequent changes of ordered item sets by customers. In this paper, two kinds of CIS system are discussed. One is a conventional pipe-valve, pump intermediate storage system and the other is a pipeless scheme of intermediate storage system. A completion time algorithm of the CIS system is also developed with two steps and it is applicable to both kinds of CIS systems. At the first step, we suggest a simplified CIS operation to make the problem easier, and in the second step we proposed the complete CIS operation as a complete flexible intermediate storage policy by inserting the ZW block in the simplified CIS operation system. Finally, we develop the completion time algorithmn for the CIS policies with nonzero transfer set-up times.