Shelf life planning

Hi

This question is with respect to shelf life planning :

Planning with Shelf Life Data in PP/DS - Production Planning and Detailed Scheduling (PP/DS) - SAP Library

What exactly is the system doing APO PPDS when it is planning based on shelf life? Is the system considering the shelf life days and keeping those in planned order created, so that these can be transferred to production order/stock when created?

Appreciate if any one can thrown light on this.