When setting up your rates availability, it is important to remember that the availability you set at the "parent" level affects what will be available at the sublevels. For example, if you set the availability at 50 at the parent level for Internet Rate, the most you could have available at the sublevel 20 Percent Off would be 50.
Inventory counters are hierarchical and inherit counter values from their parent items. Depending on where you keep inventory (rates or items) the new child item will initially inherit the parent's inventory counter until changed at the child level at the inventory tab of the inventory and availability calendar.
Adding or Deleting a Rate or Rate Plan
Setting Up Rates Quickly Using a Wizard