Oracle R12 Expense Audit Policy

We have implemented iExpenses in Oracle R12. Currently we have policy defined for 'Mileage' which requires no auditing at all and all other expenses are defined as type 'Miscellaneous' which are all audited with receipt as required.

We are now trying to implement more auditing rules and one is based on expense amount. We want to only audit expenses over a certain amount, however, still we don't want to audit the Mileage claims. I tried selecting the option "Audit all expenses greater than a specified amount' under Audit Rules, however, now the Mileage over a certain amount is also going to audit.