you better convince your business to wait for a couple months and then rethink this requirement.
You may not have the full understanding yet and have not made a lot experience.
in this tab you can add further requisitions to your PO item, you can close requisitions in case you order less than a requisition, you have to change the statistical delivery date in some case when you are using vendor evaluation, you may have to split the order quantity into several delivery dates if your vendor informs you that he cannot supply you at one time with all quantity.
Just to save you money that you may spend into a development which has to be turned off a little later.