Setup AME for Purchase Requisition Approvals

We’re evaluating AME for Purchase Requisition Approvals in 12.1.3.  Many of our cases perform sending notification through the approval chains as expected. 

The case below is the one that we’re having trouble with.

Scenario:

Requisition Total: Between 100K – 500K.

Approval Chain:

1. Approval from User 1 or User 2
2. Then Approval from User 3
3. Then Approval from User 4

Business’s desired requirement: 

1. When the Requisition is submitted for approval
2. AME sends notification to User 1 and User2
3. When User1 or User2 approves the request.
4. AME sends notification to User3
5. When User3 approves the request.
6. AME send notification to User4 for final approval.

I’ve tried many combinations of serial, first responder, consensus on the ACTION TYPE and USER GROUP definitions.