How we can configurate approval rules for two different currencies

Summary:

We have configurated 5 rules for a local currency, each rule is between a minimum amount and maximum amount for the expense report total amount. the first level ask for 1 approval, and the 5th level needs 5 approvals. We have tested and all works ok.
But now we have activated the USD currency and when we create an expense report in USD we submit the status change to "pending approval manager" and after a few minutes the status changes to "Saved".
We have try to create a new approval rule specific for "USD" but it do not work, someone knows how to eneable the workflow for a new currency without affecting the existing ones for the local currency?