2018.7.2: why is it off by one?

[evantravers]

In comparing it with Jace's output, my solution starts on node "O"
exactly one second after it should... and I don't know why. I imagine
it's either:

• possible?/3
• something to do w/ how I'm getting currently working/completed

[evantravers]

The graph of my input

My current output: https://gist.github.com/evantravers/c632330736f7845cd453531f419af4a8