Maybe it was already answered elsewhere, but here goes.
Other people can correct me if I’m wrong, because I’m not used to the inspector tab … But I’m assuming this is because it is set to “local”.
If it was “global”, then the coordinates would be the x,y and z of the actual point (computed from the starting point, so probably (-1,0,6) or something like that. If the model is exactly the same, then the global coordinates would be exactly the same as well.
If it is local, this is not the case. It must depend on how you created the wedge and how you rotated this wedge in the first place. In the course, they started with a new cube, just cut it in half and used this one without rotating anything. In your case, I guess you continued with the wedge which was rotated to point upwards. So, this rotation probably messed up the local x,y and z directions which no longer match the global ones? Also the point of origin matters …
In my case, I had x=0, y=0, z=4: I didn’t rotate my oject, but my object origin was on the base (see image), so the median was just “right above the origin (x=0 and y=0), and 4 up (z=4)”.