I see that the latest ubuntu uses systemd instead of init.d for creating the XP service.
When following the Enonic guide on how to create init.d service, it´s no problem, because this also creates a XP.service systemd service.
I would just like to point out that your documentation needs to be updated.
When systemd is in place, the correct way to stop/start/status the XP service is:
sudo systemctl stop xp.service
sudo systemctl start xp.service
sudo systemctp status xp.service
This is ubuntu 16.04 that I´m looking at.