Invoice Approval Basic Template - attribute to exclude taxes and use functional currency

Summary:

What are the attributes in the Invoice Approval Basic Template to be used to exclude taxes and consider the functional currency amount for approvals.

Content (required):

We are using the Invoice Approval Basic Template found in the Manage Workflow Rules in Spreadsheet task. I would like the approval rules to not consider the tax amount when sending the invoice for approval. Also, I would like the rules to consider the amount in functional currency. For example, if the rule says that invoices USD 5,000 and above should go for approval, the system includes the tax amount in this USD 5,000. This results in invoices with line totals of less than USD 5,000 going for approval.