This is saying the entrance wounds were not on the side of the face. The trajectory of the wounds was not straight front to back but relatively straight merely. The bullets traveled down and slightly towards the right. They were not that steep an angle but still were left to right and down.
If someone is standing at the foot of the bed and is aiming the gun at Nevill as he sit up then you get the angle of the shots. The angle of the shots can't be achieved while Nevill is standing unless someone is at a higher elevation.
Here are the locations of the entrance wounds:
Jaw wound:
Path of bullets: were slightly to the right and down ending up by the third vertebrae
This shows the path and while it might look steep the trajectory is actually not that steep. The distance is not that great.
If Nevill were standing then the trajectory would have been up instead of down. Likewise is Nevill had been lying down the trajectory would be up instead of down. He had to be sitting up in bed when he was shot.
The locations of the spent casings is consistent with him being shot while seated in bed.
Aside from the casings not being consistent with him being shot while walking up the stairs (the casings eject to the right of the weapon so would end up at the bottom of the stairs) the angle of the shots is not consistent.
If Nevill were on the stairs the further down he is the more steep the angle of a shot would be. He would have to be near the top of the stairs with the weapon close to his face to achieve the angle. He most certainly would not have continued walking up to the bedroom if the killer just shot him 2 times in the face. Yet he was shot 2 other times in the bedroom- one wound that grazed him while the other broke his arm. The location of the casings and left side being hit are all consistent with him being shot while on his side of the bed.
June is shot several times, Nevill wakes up and sits up. He is then shot 2 times in the face. He then turns to get out of bed exposing the left side of his body to the shooter and begins to rise. The killer shoots him in the arm and another grazes his arm. That is what the evidence supports happening.