Status is not always equal to PAID even though it is

$url = "$token&contact_id=".$_GET['cid']."&since=".$since."&until=".$until."&paid=true";

Sometimes status=DRAFT or status=VIEWED and not PAID even though the customer paid for the products. (example : total_paid=97).
So what is the meaning of “paid=true” in the URL ?

It’s a search filter like the other non-authorization based parameters. Meaning “return paid or unpaid orders only”