Fill rate tests quantity only. Case or unit fill is units shipped over units ordered and is the highest of the three. Line fill is lines shipped complete over lines ordered. Order fill is orders shipped complete over orders and is the lowest, because one short line fails the order. A supplier reporting case fill and a customer scoring order fill are describing the same deliveries from opposite ends. See OTIF versus fill rate versus on-time delivery.
Quantity shipped divided by quantity ordered, at unit level, line level and order level, stated which.
Ten lines ordering 1,000 units shipped 890: unit fill 89 percent. Eight lines were complete: line fill 80 percent. Two of four orders were complete: order fill 50 percent.
The highest of the three reported, and the customer scoring the lowest.