OK I am back. I had a quick job to get out of the way.
I looked at your samples. Now don't take any offense with this but your test are really meaningless. You have different everything. Different resolutions, different apertures, different SS and even different color balance. That makes it very difficult to analyse what is going on. Here are your same test shots more or less balanced in color. Although I still see some difference it may be do to aperture and SS differences. Or it could be PS changing the resolution to match Who knows by now?
When you do a critical test you need to keep everything equal as much as possible. Same light, same aperture and same SS. Same ISO, etc.....everything. Try this again and this time for instance use ISO 200, SS of 1/500 at f8 same distance and tilt of the target on all three (or whatever the lighting conditions require). I would like the FL to all be the same too but I guess that's not possible.
Here's something else to look at. Even though the 60D isn't user adjustable you can at least determine if you have a problem.