What are invoice processing costs? Is your AP Department Running .Market Perspectives from IOMA Industry Report. Evaluating your A/P Department. Effective management of working capital, defined as current assets minus.processing costs invoicing,Uncovering The 7 Costs To Process An Invoice & What To Do About .revolves around burdened labor costs for those associated with the physical processing of invoices. Rather, there are a slew of costs throughout the process that.