See how it settles over the next week then. I'm guessing you put enough and not too much AS5 on and you have made sure it is mounted right?
Also, your E6600 and aquagate block may not be making as good a contact as he did with his E6750.
What I am trying to say is neither may not be as flat as they should be. Say his E6750 was convex and the block was concave - both together would be a pretty good fit but it might be the block is concave and your chip is too - in which case, not very good contact.
If no improvement after a week I would be tempted to lap both chip and block but wait and see what happens. And you might be right about the 10 degrees. Although I didn't take note of temps the last time I used AS5, I found that my max stable overclock improved over weeks on my AMD 4200+ x2. Fresh install it wasn't happy above 2.4Ghz. Over weeks I slowly managed to gain more and more until it reached 3Ghz stable. I guess that was the AS5 curing.