Invoice approval Is very slow

I am not sure if this is the correct community for this but thought I would start here and see if anyone else has had and resolved a similar issue.  We are using AME to drive AP Invoice approvals.  Based on the value in a DFF on the invoice header and the dollar amount of the invoice, the invoice is routed through various levels of approval.  Users are complaining that if an invoice needs to go to a second level of approval, it can take up to 4 minutes or more for the invoice to register as approved at the