Ability to retrieve account balance in subledger source

Summary:

Our client is implementing RMCS and has requirement to split the initial performance amount in two different Asset Accounts basis of predefined proportion. We are able to achieve the same using subledger accounting formula provided by Oracle SLA engine. However when the billing happens the requirement is to credit the asset accounts by checking their current balance. We are looking if anyone has implemented similar requirement for RMCS accounting or in any other module accounting.