Hello. I am currently in the process of planning a flight from EGKK to KMCO in PFPX. However, I noticed that the airlines use a NAT that is pretty far south. I'm currently looking at NAT J. This track starts in the middle of the Atlantic. An airliner that recently flew this route actually used the first two waypoints of NAT F before deviating to the south to cross via NAT J. This is shown in the image below.
How is a clearance obtained from ATC to fly these half NATs? Is it normal to simply hop straight to the middle of the Atlantic and then join a NAT? I am many well confused.