TL;DRCash or invoices received for service you have not delivered yet — a liability until you earn it.
An annual fee invoiced up front is deferred on the invoice date and released month by month as the service is delivered. The balance is what you still owe the customer in service.
Deferred revenue is not used on freight: a haul is earned on its date, so there is nothing to defer.
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.