Price not getting updated on Sales Order line for Kit Item

Hi Team,

We have entered a sales order with  Line 1 as BOM item

For Line 2 : we have a Kit Item for which we have applied a Modifier say 10%.

Example : Suppose the Price of Line 1 item is Rs100.

Then the Price of Line 2 will be 10% of 100 = Rs. 10

When we entered the Items for the first time it works fine as per our expectation but when user changes the Price from say 100 to 200 for Line 1 , then system does not change it to Rs. 20

Then i do Manual Intervention that is I do Line Price Manually after this the Price on Line 2 Changes to Rs. 20 ,But my requirement is, Without Manual intervention , this should work.