In terms of anatomy, it could be something simple, like maybe that outsole has more curvature than the skater's foot... Or maybe the skate tech watched the skater skate with a centered mount, and noticed troubles? Or was matching the mount on the skater's old skates? Or maybe the skater complained that the left and right sides of the heel had unequal pressure?
Otherwise I don't understand why it was done that way. It's too big an offset at the back to be an accident, unless the skate tech was really, really bad. But some skate techs are that bad...
I think you should just watch her skate, and ask whether she would like it moved. E.g., does she tend to get a back outside edge when she wants a back inside edge? But a good coach could give better advice on what to look for than me.
I can't see that screws in the slotted holes matter - unless someone was worried about a few grams of weight.
But among the skate techs I've talked to, it's customary to remove them. I've left them in, in my skates, in case other screws comes loose - I'm not a good enough skater for a few grams to matter. But some skaters pay a few hundred dollars extra for blades which are slightly lighter than others. Maybe they think it matters?
But I'm not an expert. I mostly speak from my own experience. I once used offsets bigger than that - though they were offset both front and back, not just back. I decided it worked better for me (and twisted the boot shapes less) to center my blades on the boot, and add cloth tape under one side of the insole to equalize the left and right side pressure under the foot, or to cut foam insoles with that shape. But it is faster to offset blades, and it is what many skate techs are taught to do.