I am running a project for transportation.. I have to reduce the transportation cost. I have a baseline created with % of freight spent to sales value. The problem is multiple location and multiple mode of transport and multiple product lines that affects the weight and utilization factor. Thus I have taken grouping as months, since these variables are there every month. Thus X bar chart was drawn for the baseline than using a I MR chart with individual data points. I have close to 50 data pts per month.. Thus I MR goes out of control limits but x bar S chart is within limits.. Is this the rt way to proceed.