Related Titles: Accounts Receivable Specialist, Construction Billing Specialist, Billing Specialist, Project Billing Specialist, Construction Accounting Specialist, Project Accountant, Project Accounting Coordinator, Billing Coordinator, Accounts Receivable Coordinator, Contract Billing Specialist, Service Billing Specialist, Construction Accountant. GPAC (Growing People and Companies) is an award-winning search firm specializing in placing quality professionals within multiple industries across the United States since 1990.