The financial rate on stock or opportunity cost (I) will decrease due to the smaller acquisition batch size. If the acquisition batch size is large (Q1), there must be stocks in the automaker's plant and, consequently, the financial rate on stock (I) will be higher compared to the financial charge in a lower acquisition batch size (Q3). Thus, Table 1 shows the I1, I2 and I3 where I1> I2> I3 variables.