Min-Max Coverage is not working for AX 2009

Hello,

I have created ONE BOM, having 2 items (Say X and Y).

‘X’ item has Min-Max item coverage with Min-max Coverage group. I set Min qty as 40. Also having on hand inventory =50

For main BOM I have assigned Required Coverage group.

SCENARIO 1:

When I am raising SO for Main BOM… say for Qty 20…and after running Explosion… it is showing following results

for Y item : Planed PO of 20 qty

For X items: On hand (50) 20 ------// So here it is consuming from available On hand that is correct. But What about to maintain Minimum qty mentioned in Coverage group.

SCENARIO 2:

But when I raised SO for qty more than on hand (ie 50)… It is calculating perfect as per (qty-Onhand)+Minimum qty.

PLEASE HELP…???