Allocation rules enable size weight management. Frequently used sizes in the market are weighted higher than sizes that are rarely used or used by the minority of people. 

For example, the most common required sizes, medium (M) and large (L), need to be delivered more frequently compared to sizes extra small (XS) and extra large (XL).

After you define your size matrix grids, you can specify size weight rules in order to allocate inventory for sales orders. You can define weight rules by size for a specific grid code. Multipliers represent the weight by size. Size weight rules are used at the time that allocations are executed. For example, you might define these weights: 1 for size 38, 3 for size 39, and 2 for size 40. In this example, customers receive twice as many size 40s as size 38s, and three times as many size 39s. 

The Size Weights for Proposal table (FCW46) stores size weight information for the different sizes to be used during the proposal process. This table stores information for both allocation and delivery proposals.