Billing Document Exchange Rate Picking

Dear Experts ,

I am using the Exchange Rate type as "M" for Export Sales & Excise Invoice,in sales order, Delivery and J1IIN its picking the "M" Rate , but in billing, its picking the "EXP" Exchange Rate , i checked my configuration, screen shot also attached for your reference. how the system is picking the "EXP" Rate ? and if i change the Billing date (Previous Date) its picking the "M" Rate. why its happening in the system, kindly provide your inputs..

Thanks & Regards

Ilavarasan TD