Walk into any services firm — IT services, engineering, marketing agencies — and you’ll find the same pattern. Consultants finish the work, jot down their hours “later,” and the invoice finally goes out after a project milestone, or after someone asks about the money. One 30-person engineering firm billed clients an average of 12 days after the work was delivered. That doesn’t sound terrible until you see what it really costs.
Every late invoice is a sales problem, not an accounting problem. When a client sees an invoice 12 days after the work, the work is old news. The project is emotionally closed for them, and “what’s this for?” replaces “great, where do I sign?” Disputes take longer, payments drag on, and cash flow starts leaking slowly.
Why the timesheet is the true starting line
The ERP Consulting review at this engineering firm found something surprising: hours were collected, but nobody trusted them. Project managers adjusted the reports based on feel, and billing was rebuilt from scratch by a finance person interpreting messy notes. The timesheet wasn’t a business document — it was a suggestion.
We changed the rule at the first meeting: a timesheet entry with no project code doesn’t exist. If a consultant can’t pick a project, the system blocks the entry until it’s fixed. It felt harsh for about one week, then everyone adapted.
The invoicing rhythm that cut billing time from 12 days to 2
- Timesheets close every Friday at 3 pm — no exceptions, no “I’ll remember Monday morning” games.
- Project managers approve their teams’ hours by Monday noon; anything unapproved is not billable, and the consultant hears about it directly.
- Invoices generate automatically on Tuesday morning for all approved hours, with one quality review — not re-typing.
Within one quarter, the average invoice went out 2 days after the work. Payment time shrank too, because clients stopped questioning line items that were once vague. That slow spiral of disputes simply ended.
The finance manager told me the ERP Consulting engagement paid for itself in the first three weeks. Not because of fancy software — because of a Monday noon deadline and a screen that refused to accept laziness. The discipline was the system.