Effect on mat credit due to increase in valuation of closing stock

Dear Sir, My Assessee Company has Loss under normal provision of Income tax Rs. (800000) for A.Y. under consideration. so it has paid tax under MAT on Book Profit. The Amount Paid as tax under MAT Rs. 500000. Now AO has increased Valuation of Closing Stock by Rs. 400000. So there would be Two effect: 1. Loss would be reduced for A.Y. under consideration 2. Effect on MAT. Please guide me dat what effect would on MAT. Thanks in Advance