Sent 24-70 lens to Nikon for calibrating

Well I finally bit the bullet and sent my Nikon 24-70 f/2.8 lens to the Nikon facility in El Segundo. I use it with a D7000 and ever since I bought it seemed like something wasn't right. Sometimes I would get breath taking pictures that were sharp as a tack and sometimes they'd be a bit soft. I got a LensAlign system to see if I could do some micro adjusting and I found that sometimes it would front focus and sometimes it would backfocus. It didn't seem to do that with my Nikon 70-200mm f/2.8 lens so I'm pretty sure it's the 24-70 lens and not my D7000 body. I sent in the camera with it just in case it's the camera. Sucks having to mail equipment that costs so much $$ but I just got so frustrated I couldn't take it anymore. Anyone have any positive experiences from sending a Nikon lens/body to Nikon for repair?