The Cooperative Logistics Supply Support Arrangement (CLSSA) is a program designed to provide follow-on supply support for weapon systems procured by foreign military sales (FMS) countries from the United States. CLSSA calculates a Stock Level Quantity (SLQ) for each item based on demand history, item lead-time, and requisitioning patterns. Item SLQs affects program cost and service levels to FMS customers; a high SLQ level improves service levels, but also creates higher costs. The author created a model to replicate the CLSSA formulation used to calculate SLQs, using different combinations of demand levels and item lead-times to determine the impact that different ordering patterns have on SLQ levels. The results provide optimal ordering patterns for the various combinations used in this study to ensure maximum service levels while minimizing customer program costs. Although each different combination of demand level and lead-time produced a specific optimal ordering frequency, in general, items with lead-times of 24 months or greater, 12 months, and 7 months or less, had optimal requisitioning frequencies of annually, semiannually, and quarterly respectively. The complete results can be used by FMS countries to tailor their CLSSA requisitioning strategy to meet their needs of service levels and cost.