Differences among Limit to Committed, Allow Uncommitted and Ignore Commitment

Limit to Committed defaults to fulfill the committed items and quantity.  User cannot add other items to the fulfillment that are not committed (those items that don't even appear), or increase the quantity beyond the committed quantity.

Allow Uncommitted defaults to fulfill the committed items and quantity, but users may select other uncommitted items, and increase the quantity of committed items beyond the committed quantity.

Ignore Commitment defaults to fulfill all unfulfilled items and quantity, regardless of commitment.