AU: Setting Abregel Thresholds - Explained

Hello,

Does anyone know which databases are used to determine the target speed ranges for the vehicle inspection (AU), which are also printed on the certificate?

Regarding my old Golf 3, after three emissions tests in 2000, 2002, and 2004, the following data was recorded (target values: minimum / maximum / actual values in rpm):
1. 4800 / 5200 / 4980
2. 4800 / 5200 / 5150
3. 4800 / 5600 / 5333.

The last result surprises me, especially because, considering the somewhat "tight" result of the 2nd inspection (after a correction of the ESP calibration at that time), I checked the rev limiter with VAGCOM together with the current owner shortly before the 3rd inspection.
The result was 5124 rpm, which was maintained consistently for approximately 2 seconds.


Could VAGCOM potentially display "incorrect" (i.e., lower) RPM values, especially in the higher RPM range, that are beyond what would be expected from the 21-RPM resolution uncertainty?

There is definitely a discrepancy in the same direction between the stepper motor-driven tachometer in my Polo and VAGCOM.
Up to 3000 rpm, both devices show perfect agreement; that is, when there's slight fluctuation around a scale mark, VAGCOM always displays the next value either below or above it.
However, around 3500 rpm, VAGCOM falls behind the tachometer: at 4000 rpm, it's about 2 grid values off, meaning it reads values like 3948 or 3969 instead of the actual 3990 or 4011 rpm.