AX Ignoring receipt margin


AX 2009 is ignoring my receipt margin when planning.

I have a Z item manufactured with an A item with a Lead Time of 30 days and I am going to plan with a receipt margin of 7 days for the raw material.

So if I have a production order for Z item for less than 30 days AX will show that the order will be ready 37 days from now and show the future messages. And if the production order its planned for more than 37 days from today it will show that the purchase orders are placed 37 days before its production order.

Here comes the problem: if my production order is planned for more than 30 days but less than 37, AX will not consider the receipt margin and show me that the order will be ready 33 days, for example, from now.

Thank you.