Hard to judge for sure by the different angles, but based on that front view the AR position looks better to my eye. For example, if you compare where her elbow is relative to her knee, on the AR it is much lower. On the AR, she is essentially doing a mini-mantis, with her elbows a bit below her hands. On the Trek, it is the other way around, with her hands below her elbows. That shrug is probably also contributing to getting her head a bit more out of the wind. On the Trek position it is very exposed and non-aero.

When you said that her fit was based on her road fit, did the fitter at least try to replicate the aerobar position? It sure doesn't look like it to me.

Note that position is really king in aerodynamics. A good position on a road bike with clip-ons is better than a bad position on a TT bike. The bike itself is really not that much drag. Usually a TT bike should let you get into a better position, but it isn't automatic.

ETA: The other position key I look for when I look at my own position is where is the chin. On the AR, her chin looks almost level with her hip bone. On the Trek, it looks a good 4-6 inches above. Again hard to be 100% sure from the very different angles of the pictures.