"What Andy Ibbott refers to (I think) is that you can accelerate harder the more upright the bike is, so by squaring of the corner you get upright sooner and get on the power sooner, but at the apex you will still be leant right over."-True-ish.
What he actually advocates is turning the bike faster-the faster you turn it the less time it is leant over and the less lean angle you have to use. The result of this is that you can corner quicker for any set speed, and get on the power quicker as the bike is upright quicker.
Here endeth todays lesson.
John