Production forecast not consider in requisition worksheets

Environment : 2009SP1

Item Card : ABC
Replenishment System : Purchase
Reordering Policy : Lot-for-Lot
Include Inventory : Yes
Purchase lead time = 2D

Production Forecast : 2010Q4
Item : ABC
Location : Blue
Date : 01-Oct-10
Oct Qty : 1000
Date : 01-Dec-10
Dec Qty : 999

Sales Order :
Item : ABC
Location : Blue
Shipment Date : 12-Dec-10
Qty : 30

Inventory :
Item : ABC
Location : Blue
Date : 14-May-10
Qty : 3

Calculation plan :
Item : ABC
Location filter : Null
Start date = 01-Jan-10
End date = 31-Dec-10
Production forecast : 2010Q4
Exclude forecast before : Null

Result of requisition worksheets :
PO suggestion : 27 Qty ABC, Due date 12-Dec-10, order date : 10-Dec-10.

It seems there is no consideration of production forecast that I specified in the option tab. Why?

Is there any missing setup?

Thanks!