Optimizing Supply Chain Network (SCN) system, otherwise known as "strategic decision", with assembly line balancing issue (tactical decision) is relatively at infant level in literature. Managers and decision makers usually will not disregard either of these activities (either disregard SCN activities while trying to balance assembly lines or assembly line balancing while designing an SCN) for an SCN system that has assembly line unit. These two key subjects are collaborative. This work focuses on advancing optimization criteria from one of the pioneering work in this research field by designing a mathematical model to optimize the SCN that includes the manufacturers/producers, assemblers and end users. The goal is to simultaneously minimize the transportation costs along the SCN line for the concerned time phases while balancing the assembly lines in assemblers so as to minimize the overall cost of setting up stations. A mixed-integer nonlinear model is proposed to minimize the transportation costs alongside the cycle time and number of stations at the assembler. This means minimizing the idle time and also maximizing the line efficiency by increasing the throughput rate in addition to the cost minimization. We propose to apply the model to real life data and subsequently recommend its deployment.