VW has 3 sets of ignition timing tables. Base (main ignition set point), Minimum, and Reference Tables.
The reference tables are used to
iga_dif_av is a representation of the Actual Commanded Ignition Timing vs the Reference Ignition Timing. This is a 1:1 translation, so what we are seeing here is a 35 degree difference between the two values. The system is intended to correct the reported torque value so that it is an accurate representation of the torque output from the motor. The value in iga_dif_av is referenced in the Ignition Timing Correction Torque Efficiency High/Low Lift Tables. This is where we get the multiplier for the monitor Ignition Torque SP Efficiency Vlft High/Low.
The value Torque SP Efficiency Vlft High/Low is multiplied against your base requested torque set point.
The solution here is to make the reference ignition timing values and your base ignition timing values closer together so that the value in iga_dif_av will fall into an area with less of a penalty to the torque values. A value of -13 to -17 in iga_dif_av will have a 9% change to the torque value at most.
I have some idea of disabling this system (once I can get the XMLs working again). Last time I was messing about in this area however we removed ALL torque reduction, which was not good for the DSG shifting at full throttle.
Let me know if you have any questions.