Can I Use the Duty Value (i.e. TDTY) in an Expense Calculation?

I am trying to get use the Duty value in a CVB so that I use that in the calculation of an expense, but I am not able to do so, even when changing the Computation Level so that the Duty is calculated first than the given Expense that uses the CVB that has the Total Duty Component.

I am thinking that in Oracle they both work independently and there is no interaction between Expenses and Assessments what so ever, but I am looking for confirmation.

Thanks in advance!

Felipe Barros