Why are Bandwidth Control rules evaluated only on the first 10 packets per session?

Often rules involve session metadata such as HTTP-Hostname or Protocol-Control-Signature. Detection of these metadata tags is usually completed fairly quickly, within the first few packets, but it's not immediate. As such, the session is evaluated on the first ten packets to ensure that all rules that involve metadata have a chance to fire. After the first ten packets, the metadata typically does not change and the rules are no longer consulted.