i don't have a 7D, but had a similar problem with my T1i (due to heavy condensation problem after being out in 90+ degree heat on July afternoon, and came into air conditioned house w/o putting it in a ziplock bag first). Even though the camera beeped with its center point focus locked, even if it looked sharp in the view finder, it was out of focus on the final capture; and sometimes it beeped for focus and looked UNfocused even in the view finder.
I had the convenience of having a friend who lived nearby with another canon camera (T2i); I purposely took almost a full 1/2 day testing all my lenses on friends camera: (tripod/ISO 200/Manual Exposure/ Av: f/8.0/ Tv: 60/ PicStyle:Faithful/ 2pics each lens: 1 Autofoucs, 1 Manual Focus / Subject: took picture of same 8x10 printed photo card / exposure comp was necessary in many cases by +/- 1/3).
In the end I was certain it was not the lenses. It was my camera. I discovered it was worse in shallow contrast situations than with high contrasting situations. Still in warranty I sent it to Canon. they serviced it for free. Sadly It's still not perfect. 1/10 shots still obviously out of focus, another 1/10 marginally out of focus (soft). So, my camera is only at 80% in my opinion. As i'm upgrading in June, I haven't thought much of it.
You're aware that by sending just the lens for calibration (and not both the camera and lens) there's really no way for them to match them together? If your point in calibrating was to make it work its best, it's best to send both the lens and the camera and the calibration will be spot on for that combo.