Approver removed from custom approval workflow after bill amount was changed

We have a custom approval workflow script in place for Purchase Order and Vendor Bill approvals. We recently experienced a situation that resulted in a person being removed from the approval workflow when they shouldn't have been. Accounts Payable entered a bill, and upon saving, and based on our approval workflow script, the list of approvers needed was created. After the first person approved it, it was with their supervisor. At this point, Accounts Payable had to update the amount of the bill to increase it. When this happened, it added 2 new people to the approval flow, however, the