Warren County government’s decision to outsource its ambulance service billing could be paying off to the tune of $200,000 in additional revenue.The county voted in January 2016 to enter into a three-year contract with AMB, a national ambulance billing firm that specializes in obtaining payment for services provided by ambulance departments. According to EMS director Preston Denney, he met with AMB representatives last week to discuss some issues his department is having with AMB software and received an update on the financial situation. AMB charges 5.75 percent per month of its net collections.