I'm not so sure about the quenching being of no consequence. Usually with non ferrous materials, one quenches to keep material soft, whereas with steel one quenches to keep it hard. Slow cooling with non ferrous alloys usually promotes what is called precipitation hardening which involves a particular type of grain growth that occurs during slow cooling.
If there's a need to control grain growth, the brass got way too hot. The specific reason for using tempilaq and keeping temperatures low is to prevent changes to the grain structure.