goods Issue not at MAP

Sir,

    In PS when I do Transfer and posting (412 Q) and Goods Issue (281 Q) for Inventory consumption, the goods are issued at the rate which appeared as MAP at time of first issue.

If More GR is done in inventory at some different price (i.e. MAP changes),additional GI to Project is done by old MAP only.It does not pick the then MAP.

I want that the goods get issued at MAP at that particular moment. Kindly guide for configuration/parameter