Here's the deal with MNS vs. MNR. Months-No-Sale (MNS) is the last time you sold the item. Months-No-Receipt (MNR) is the last time you purchased the item. The aging process occurs on both sides. Let me use the example I always use. I admit it's extreme but does emphasize the point. Let's say you have a particular SKU (item or part) that sells at a rate of 2 per week. That's approximately 100 units per year. You get a great deal on this item and purchase 200 units. Yet, you continue to sell the item at a rate of 2 per week. On the MNS side, because you are selling 2 per week, the remaining inventory value is current and reflected in the 0 to 3 MNS category. On the MNR side, because the item may have been purchased greater than a year ago, the remaining inventory balance is aged to 12+ category. Another example of how this condition occurs is when days supply is incorrectly set and ordering occurs in excess of demand. In the two aforementioned examples its' a reflection of excess stock. On the other hand, when MNS is greater than MNR in any of the inventory movement categories (0-3, 4-6, etc.) sales exceeed purchases. If this variance is excessive then the Parts Department may find that it is running short of customer demand. A balance should be maintained in the most active inventory categories (0-3, 4-6). As for the remaining aging categories the ideal situation will be if the variance between MNS and MNR is a wash or zero, or if the MNS for each of the categories (7-11 and 12+) is slightly greater than the receipts. Remeber, a balance. You buy what you sell; sell what you buy. ADP has been listing Inventory Movement-Sales (Months-No-Sale) and Inventory Movement-Receipts (Months-No-Receipt) info. on the MGR Monthly Summary report since I can remember. Few Parts Managers have really understood the relationship and therefore ignored the receipt info. as part of inventory movement analysis.  source: Gary J. Naples, dealersedge.com forum

MNS vs. MNR