In our service business, a project often takes weeks to complete, but labor and other expenses are incurred throughout the project period so we often ask for advance or installment payments. Since a final invoice amount often isn't known until the project is complete, we invoice at the end of the project and receive a final payment for the balance due. Under the current system, the advance payments received are recorded as a liability, but in our case it is actually income for services provided (labor costs, etc.) during the project. The current system imposes accrual based accounting on our cash based business. I imagine this would apply to many service based businesses. Thanks for your consideration!