I'm not even in a consistent 18sec avg but I JUST GOT MY FIRST EVER SUB-18 AVG OF 12!
The avg is 17.53(new PB). I dont have the times but from what I remember the best time is 15sec & worst time is 21sec.

On a side note, I got my first sub-1 minute (55.94sec) one-handed with RIGHT HAND today. Very g0od!