What is over and under billing (and the WIP report)?
Over billing means you have billed more than the work completed to date, and under billing means you have billed less. The work-in-progress (WIP) report compares billings to earned revenue across all jobs, revealing over and under billing, and it is a standard requirement for bonding companies and lenders because it shows the true financial state of the work.
Why it matters
Under billing is unbilled work, real money you have earned but not invoiced, which quietly starves cash flow. Over billing can flatter your books and leave you short later. The WIP report makes both visible so you can correct them before they hurt.
Why bonders and lenders ask for it
A WIP schedule shows percent complete, billed versus earned, and remaining backlog across every job. It is the clearest single view of a contractor's financial health, which is why sureties and banks rely on it, and why QuickBooks alone usually cannot produce it.