Need to create a Rounding Off Amount Line for Payable Invoice Automatically

In Some of the countries it is very general scenario where Supplier Invoices includes the Rounding off amount as separate line or Separate Field.

 For example In Supplier Invoices there is total amount available as 111
and Line 1 is laptop 100$
than tax amount is 10.87$

 then Line total is 110.87
Rounding off amount is 0.13$

 so that Total Amount is 111.

 When we create the same invoice in system we will keep 111$ as Invoice header Amount than we will create Line 1 as 100$
Then tax will be calculated as 10.87 when we do the validation and if calculate tax is done before the validation then after the validation , system will put hold for line variance due to rounding off Amount 0.13