Forward consumption of PIR

I am using planning strategy 63. Using consumption mode 3 for backwards and forwards, it is properly consuming backwards. But it does not seem to do any forward scheduling even though I have a forward consumption period of 999 days. In fact when I book a new order it gives me a date in a period that is full. Then I look at MD73 and can see it is considered "non-allocated" there even though it is confirmed.

I beleive I have everything configured properly as I have read all the SAP documentation I could get my hands on. I am on version 4.6C. Has anyone else had this problem?? If it consumes the planning material backwards I don't understand why it won't go forward.

Any and all help is appreciated!! Many thanks for all your help in advance!!

Debbie