Cputeq, I have owned 7 ZE lenses, and what you are experiencing is not unusual. My 5DII had to go in for a shutter replacement, and, when it came back, it was not "adjusted" the same as previsouly. My guess is that this is the cause for lenses going slighly past infinity: to cater to camera tolerances. As to what this means in real terms: nothing. I just "learn" where infinity is on each lens, and go there instinctively, rather than "flat out".
Have fun with your new lens! It looks like you already are...