InstraMatronics, a distributor of electrical monitoring equipment, is looking to reduce inventory costs. Hal, the new materials manager, is considering the inventory policy for HS008, a popular device used to monitor and control many environmental conditions in manufacturing settings. Hal has recently discovered that over the last 5+ years since the HS008 was added to the InstraMatronics product line, the inventory of HS008 has never fallen below 41 units and is typically much higher, even just before the arrival of new shipments. These high inventory levels have provided a 100% service level and very high inventory holding costs for these expensive devices. Hal would like to accept a lower service level (88% during lead time) to reduce holding costs.

The lead time to receive orders from the supplier in Japan has consistently been about two months. Currently, InstraMatronics has 1178 units of HS008 in inventory, and there are currently no outstanding orders for additional inventory. This is the only product that InstraMatronics orders from this particular supplier. The estimated transaction cost per order placed is $100, and the annual per unit inventory holding cost is considered to be 24% of the purchase price. The supplier offers discounts for large orders. The pricing works as follows: Order Quantity Unit Price Item: HS008 1 299 $500.00 Supplier Location: Japan 300 999 $480.00 Constant Lead Time: 2 Months 1000 + $470.00 Sales data for the 5+ years that InstraMatronics has carried the HS008 is given in the InstraMatronics Sales Data spreadsheet. During the last 4+ years, a new forecasting system has been in use, and forecasts are shown alongside the actual sales data. Also included are future forecasts for the next several months.

While InstraMatronics has chosen to keep records of sales on a monthly basis (see spreadsheet), this is unrelated to inventory replenishment options. It is very possible to order from the supplier with any frequency desired (e.g., small quantities could be ordered several times per month, or large orders could be placed every few months, etc.). Orders can be placed at any time during a month.

Hal would like you to recommend a continuous review inventory policy for HS008. This new policy will work as follows. Based on the values of Q and R that you determine (assignment below), when the inventory position falls to R, an order will promptly be placed for Q units.

Question: Create a graph of the sales data and forecasts from the spreadsheet.