From the model Ⅰ we can see: c_s1 refers to the cost of handling service which is provided by handling facilities in unit time, when〖 µ=1 . c〗_s1µ refers to the cost of handling service which is provided by the single desk in the unit time. However, in model Ⅱ, c_s2 refers to the cost of handling service which is provided by every service desk in the unit time. The refore, the meaning of 〖 c〗_s1µ in model Ⅰ is equivalent to the meaning of c_s2 model two. From this we can see, in the case of other conditions are same〖,c〗_s1µ=c_s2. Supposing 〖c_(s=) c〗_s1 , then c_s2 s=c_s1 μs=c_s μs.