I have added extra charge and deducted discount from subtotal in sales order but I want to create invoice with deducted discount and added surcharge amount in sales order.

For eg. I have created a sales order with subtotal of 1550rs. and less discount of 50 rs. and added surcharge of 100 rs. So I get the total amount 1600 of sales order. I want invoice to be created with total of 1600rs. after deducting discount and adding surcharge.

May I get some solution on this?