Calcualte Plan in Planning Worksheet

Calculate Regenerative Plan
When you calculate a regenerative plan, the program plans for all items. This might be necessary if there have been changes to the standard data or capacity since the last planning, which would effect the total plan and, therefore, all items. An example of such a change would be an adjustment of the shop calendar, which could influence the timing of the total plan and all items.

When you click Calculate Regenerative Plan on the Functions button, the batch job request window appears. From here, you can run the Calculate Plan - Plan. Wksh. batch job. You can get specific Help for the batch job on the request window.

Calculate Net Change Plan
When you calculate a net change plan, the program plans only for those items that have had the following types of changes to their demand-supply pattern since the last planning:

A direct change in the demand requirements for the item. This could be a change in a forecast, sales order, purchase order, production order, or production order component line, for example.

A change in the standard data and/or planned supply for the item. This could be a change in the BOM or routing, the definition of safety stock or reorder point, or unplanned inventory discrepancies, for example.

The reason for calculating a net change plan, as opposed to a regenerative plan, for example, is to save time and system resources. It is not necessary to replan items whose demand-supply pattern has not changed since the last planning.

When you click Calculate Net Change Plan on the Functions button, the batch job request window appears. From here, you can run the Calculate Plan - Plan. Wksh. batch job. You can get specific Help for the batch job in the request window.

This is from the Help. What are you not understanding?