Sounds like a good suggestion to me. My lap was pretty half-assed . I can't lap my HSF because i don't have one, water block.
And I'll add while everyone seems to be suggesting that a 7-10 degree temp difference isn't really a big deal, I beg to differ. While I agree that it won't impede performance and in the grand scheme of things it won't hurt your processor, I don't think one core being 10 degrees higher than another one is necessarily a good thing.
The way most temperature monitoring software works is by showing an overall temp of the highest core. I'm not certain, but I think one or two show an average temp of all cores. Regardless, the point behind buying the best cooling products and maintaining the lowest temperature we can afford to is number one: to lengthen the life of our components under the abuse we put them through, and number two: let's face it, to brag about how low our temps are and how little we had to spend on it.
That being the case, If I have a highest core of 38C with a 3.24 OC, and this other guy brags about 34C on his, but come to find out he's got two cores that are 44C, it's an inaccurate claim. While I understand that that alone isn't a big deal, it's only one side of my argument. The other thing to consider is that if one load temp is considered in the "safe zone" at 66C and the others are around 76C, then you've really got to do a little more work to get those temperatures better. Otherwise, you're over-stressing your components, and you could potentially risk killing them years earlier than necessary.
A few things could be the culprit, and it's not always a good lap job that would fix it. Your problems could range from uneven lapping, bad TIM application (not enough, too much, uneven coverage), one side of your HSF being too loose or too tight, or even your HSF not being centered. Granted this is not an exhaustive list of possibilities. I am hardly the expert to provide that sort of information. That's just what my first things to check would be.
Try taking off your HSF and seeing the pattern of the TIM. Is it completely even? My TRUE needs to be mounted better, so it's not as tight as it should be. As a result, it twists some while mounted. If I were to take it off now, the TIM would look horrible. It would probably be close to bare in the center. But that's what's making my temp as high as it is. My point is, it could be something as simple as that that's keeping your temps uneven. Or if you have a bad lap job, then your TIM pattern could show that. (I think I want to re-lap my TRUE, I kind of did a rush job on that, but took my time on the CPU)
Hopefully no one wants to fight me now. I didn't mean to piss in anyone's Cheerios.