I can say with considerable certainty that there is a large difference in the results of a power assurance check accomplished in the C+ between the number 1 and number 2 engines.
You can take time of year, wind speed and temperature out of the equation and most times the number 1 engine will check out rather strong while the number two engine's numbers are decidely less.
I've experimented with nose into wind, out of wind, offset slightly; it just doesn't seem to matter. The airflow has got to be different around the number 2 intake, because I can see no other reason for the engine on that side to always come out a lot lower in PA checks than the number 1 side.
What gets me is the sheer amount of energy most people are willing to put into fudging these checks (DDR versus chart) instead of intelligently trying to figure out what's wrong in the first place.