'Seriously advanced' was perhaps the wrong way to say it Bill.
Yes, I'll post some new logs during the week and let you know...
The air/fuel mixture takes time to burn. Ideally, it should be ignited at the correct time so that maximum burn is occuring just after the piston has passed TDC (and is moving downward) - so pushing the piston down the cylinder with the greatest force. If the maximum burn (and maximum pressure) occurs a little later then the 'push' on the piston happens a bit late and power is wasted.
In other words, you have the right volume of the correct mixture in the cylinder - at the correct boost pressure your turbo has delivered, but some of the potential force the combustion of this mix could have given is wasted - because it is applied fractionally late. (advancing the timing can correct this, if you can overcome knock)
Of course, as Bill rightly says, ignite too early and the maximum burn could happen too early, resulting in max chamber pressure acting on a piston that is still travelling upward. Here, you will get detonation and lost power.
Does that explain sufficviently why MAF readings won't increase, but power will?
Also - bringing max burn closer to TDC rather than after it allows maximum cylinder pressure to oppose the tensile force acting on the conrod......