I'm no expert and I can't refute their measurements. But, I just changed out my LR strut and as tight as things are I cant imagine that boring out the holes at the base of the strut would do much for long. I can see how more play would allow more in/out movement of the knuckle, and that would allow a bit of camber adjustment, but the only thing that would hold it there then would be the flanges of the two through bolts/nuts pinching the strut mount against the knuckle. I would guess that you could easily load that area up and create some movement. Again, just thinking out loud. There are adjustable arms attached to the base of the knuckle on the rear but I guess those can only change toe?
I have a couple of local retailers that advertise a free alignment check. I think I might get a second measurement and opinion and see how that goes. I did have a Ford van for a long time that always measured a bit out on caster. They always wanted to drill out and shim the strut mounts in front. I always declined. Never ruined a set of tires. Sometimes had a bit of pull but I just didn't like the sound of it all.
Good luck with the decision. And let us know what you learn.