TL;DRThe span of days a shipment invoice groups hauls into — daily, weekly, or monthly from the contract start.
Freight has no billing period in the subscription sense; it has a window. Windows run from the contract's start date — a weekly contract starting on a Wednesday bills Wednesday to Tuesday — and the days left before the contract end are a stub.
Invoices group by contract, shipper, and window; the invoice date is the window end. A one-shipment invoice can carry the mapped document number from the file; grouped invoices get a generated one.
Where it happens in Sonic
Next
See it on your contracts
A walkthrough on the agreements and files you actually bill from — not a slide deck.