pricing problem

hi all,

while i am creating sales order in exports when i enter the conditins like BASE PRICE,FRIEGHT, then it is working fine. it is showing the total net value properly.

But, as soon as i enter INSURANCE condition then it is clearing the net amount value which was there earlier and it is overwritig the old net value with INSURANCE value.

Ex:

till now base amount + freight = 10000

Now if i enter condition INSURANCE with value 100,

then the net value is getting changed to 100.

Plz help me out ASAP.

Thx & regards,

Pawan