Good morning Tim and Steve,
Steve, while you are quite correct in how to create your own points, unfortunately changing the coordinates in the new POI you created, does not update the location of the POI, the point will be created exactly where made it. Unfortunately we find that too most users do not know that coordinates come in many different formats, and input the coordinates in the wrong format, ending up in a wrong location. So we refrain from using coordinates.
The only way to do it, is to find the location on Google Maps, turn on satellite view, and to see what is nearby - in this case I can see Amalinda, Big Cave and Farmhouse, that I know is on T4A.
In the trip planner, I searched for Amalinda lodge to get to the right vicinity. On the right hand side of the screen you will see a "layers" button - if you can't see the layers button, click on the blue icon at the top, all the icon options will disappear and it will be easy to see the layers button.

Select the "Mapbox Hybrid" option in order to see a satellite view - you will see similiar points and images on the screen (it will not be identical to Google satellite view)
You now have to compare the two sat images, in order to try and find the right location - you will see while Khayelitshe House appears on google, Mapbox shows the lodge but does not have the name.
Once I locate the lodge on the trip planner, I can now follow the process to create my own custom POI - in this case it would be great if you could also "suggest a correction" and bring it to our attention that the lodge does not appear in our maps, and we will fix it!
The coordinates that shows in your custom POI, will now be correct - I usually name the new POI but leave the coordinates behind the name, should I need it at a later stage.

If you now switch back to the T4A map, you will see that the gravel road leading to the lodge is already in the map, so you will be able to navigate to the lodge with the T4A products - but be aware that if there is no road in T4A to your custom POI, you will have to add custom road markers along the way, to enable you to follow the route to the lodge - this should be easy enough to do with the satellite view enabled on the trip planner.

I've added the lodge to T4A now so it will show in our next update!
Safe travels!
Regards/Groete
Lizette
Lizette Swart