If a product is managed in stock, in the Product-site, Planning tab, there is a field called “Coverage” that is expressed in weeks and a number can be entered in there for MRP to consider when it runs. This Coverage field is controlled by a parameter called MRP reduce coverage stock "MRPRECOVST" and it is found in Setup, General parameters, Parameter values, STO chapter, SCH group. For every transaction that is covered in a period, MRP compares the stock level and the reorder lead time with the actual requirements (orders). When the reorder lead time is too low and the stock level on the date of the planning is ran, MRP can generate a suggestion and it displays the results based on the selection of that parameter:

No: MRP process must analyze the requirements inside the coverage period and generate a suggestion to cover the demand.

Yes: MRP process must analyze the requirements inside one coverage period and only generate a suggestion at the start of the coverage period.

For example, if the “Coverage” field on the Product-site is set to three weeks, MRP parameter “MRPRECOVST” is set to “No”, Replanning rules are set with 160 days backward and forward, and there are several sales orders (demand) for the periods/months (April, June, and July):

When running MRP processing then viewing the Enterprise planning, you will notice that the system created a separate PO suggestion for each sales order as the requirement analysis was done to cover each period of the demand. 

When MRP parameter “MRPRECOVST” is set to “Yes” and the demand is the same, running MRP processing will show a PO suggestion for the first period then it will combine the remaining periods together.