(this is all as I understand it)
There are two things here: racial max and augmented max, and I think they have been sloppy with wording occasionally.
Your augmented maximum is always four points above your unaugmented attribute. If your strength is 3, no mix of 'ware and magic can take it above 7. But if you use karma to buy it up to 4, then your augmented maximum is 8.
As a human, your racial max is 6. You can buy your strength up that far with karma, but no farther (unless you get the exceptional attribute quality, when it could go to 7). So from starting at 3 you could pump in 75 karma and get up to strength 6, at which point your augmented max would be 10.
The spot that I'm not clear on is with cyberlimbs. I've assumed that limb attributes, after all is said and done, can't exceed your augmented maximum, but I'm not positive about that.