Color Balance at AdoramaPix

I recently had a picture, that I liked a lot, printed at 16x20 at AdoramaPix.  It was a jpg image straight from the camera.  After looking at the result (which I also liked a lot), I decided that the nuisance imperfection in the lower left corner of the image was indeed annoying me.  So, I photoshopped it out, replacing it with background.  I then applied a bit of sharpening to the image, saved it to a jpg file, and ordered a new 16x20.  The new print looks great too, but different.

The first print is a bit darker and the colors are definitely slightly more muted.  I'm curious if anybody has an opinion as to what is causing this.  Is it just random fluctuations in the printing process?  Is it an artifact of sharpening?  Seems unlikely.  Does Photoshop do something I don't understand when it re-saves a jpg?

Any thoughts?

-barry