There is also half a second with my route too. If you look when you got the first flag and when i got the first flag, we are about 1 second apart. Suggesting that if i didnt have a slow start my game would have been very low 18.
you're onto it Mike - there is definitely a second between us in the start... just try settling for a fraction of a second before powering at the edge.
As for the rest of your run... if you could take the second off at the start, and manage what a few have done by wheelying out of the left cave, keeping your front wheel off the glue, then you could knock another half a second off.
your route is possibly a sub 18 second time with my start