iPhone 11 Pro fast charging

How do I tell if my iPhone 11 Pro is fast charging? It only made one chime when I charged it at 30% battery level with 18W, 30W, and 60W Apple power adapter and lightning cable. Is it suppose to make two chime with fast charging when battery is below 50%? Call Apple support and was told that it was suppose to indicate that it was fast charging on the screen but I couldn’t confirm this anywhere.