So, she placed 18 darts (3-at-a-time) in the treble ring. While larger than the bulls-eye, the triple 20 is worth more (60 points) than the 50 points of a bullseye.
The world record for Ton-80s is 22 in a single match.
I've gotten ONE triple-sixty years ago, and was quite proud at the time. The biggest challenges for me were "bounce-back" when hitting the wire and "dart-splitting" (Robin-hood style).