Agency Invoicing Checklist

Open the job in Workamajig (or Function Point / Advantage) and confirm the SOW is countersigned and dated. Bill against the executed scope, not the verbal scope — invoicing past an unsigned SOW is the most common reason AP kicks an invoice back.

Lock the period in Harvest or the Workamajig timesheet module. Chase any open hours from creative, strategy, and producers before the cutoff — late timesheets entered after invoicing turn into write-offs or awkward corrected invoices.

Reconcile production company, post house, music license, stock, and freelancer invoices against the approved bid. Flag anything billed above the bid line so the producer can resolve before it hits the client invoice. Attach PDFs as backup.

Match the line-item format the SOW specified — retainer fee, T&M with rate card and hours, or fixed-fee deliverables. Some clients (especially CPG and pharma) require line-item detail; others (financial services) require a single retainer line. Use the format their AP expects.

Apply the mark-up rate stated in the MSA (commonly 17.65% commission-equivalent, or a flat 10-20% handling fee). Procurement-led MSAs sometimes prohibit mark-up on certain categories — re-read the billing schedule before applying.

Advertising services are taxable in some states (e.g., parts of NY, OH, TX) and exempt in others. Use the client's bill-to address, not the agency's office. Production deliverables may have separate tangible-personal-property treatment from service fees.

The AD owns the client relationship and must sign off on what gets billed — including which write-offs to absorb and which to push. Capture the decision before sending to finance for the WIP review.

Reopen the draft, apply the requested write-offs or line edits, and re-route to the AD for a final OK. Document the change in the job notes so the next cycle's invoice does not reintroduce the same issue.

Pull the active PO from the client procurement portal (Coupa, SAP Ariba, Workday) and confirm sufficient remaining balance. Invoices submitted against a closed or exhausted PO are auto-rejected and cannot be appealed without a new PO.

Submit through the client's preferred channel — Coupa / Ariba / Tradeshift portal, AP email inbox, or EDI. Save the submission confirmation; this is the date that starts the Net-30 clock, not the invoice date on the PDF.

Review the AR aging in Workamajig at the 30-day mark. Anything in the 31-60 bucket needs an outreach plan; anything pushing 60+ should be flagged to the AD and managing director before it ages further.

Email the client AP contact with the invoice number, PO number, submission date, and PDF reattached. Copy the day-to-day client contact for visibility but address AP directly — the day-to-day rarely controls payment timing.

If AP has not paid within five business days of the Net-30 nudge, brief the AD with the invoice and PO details and ask them to call the client lead. Finance-to-AP email chains stall at 60+ days; a relationship call from the AD usually unblocks it.

Match the ACH or wire to the open invoice in Workamajig and the GL. Watch for short-pays — clients sometimes deduct a write-off the AD did not approve. Short-pays need a documented decision before closing the invoice.