I'll pop something here quickly...
Basically log block 114 as you would any other (under load through the rpm, we tend to do this as it loads the car up more than normal or even aggressive driving so helps see the maximum values)
Block 114 shows you specified load, corrected specified load, actual load and wastegate duty cycle.
You would expect to see (when you're on the throttle) the first three values being almost the same. If corrected specified is more/less than specified or actual then the ECU is having to alter requested values based on readings from one or more engine sensors. It would do this for a couple of reasons... incorrect tuning/settings (depending on whether you're running adjustable software or not) or a fault somewhere.
If for example you had a boost leak the corrected could well be more than the specified but the actual will be much less... so the ECU is seeing that requested values aren't being made and is trying to ask for more to compensate. It would only be like this until the ECU hits a limit or goes into limp i.e. it realises there's a
problem. Wastegate duty cycle isn't always going to ask for the maximum values as the majority of VAG turbos can't hold much boost as they get higher up the rev range so duty cycle and requests drop off rather than attempt to ask too much of it. Again though this depends on how the car's been tuned.
In regards to loading on a dyno, with too much load (in comparison to average road conditions) the ECU will see that the car is 'struggling' so will over compensate and request more thus the car gets hotter quicker tends to peak early and heatsoak; results normally see lower than expected BHP but high torque levels.
Hope this helps a little!