Hello, I am the 'new'

.
I've been reading here for quite some time now...
I have a 20-year-old Golf 3 TDI GTI with the AFN engine.
I recently bought a chipped engine control unit from a friend at a good price.
which he, according to his statement, had optimized with a car at either 'ertl' or 'örtl'.
The control unit is a 028 906 021 DF control unit.
The car is running okay so far; I adjusted the WFS (Warm Function Start) using VAG-COM.
Now I would like to ask how the MFA values change.
Or, to put it another way, are they still 'credible,' or does anyone know?
Anything about the tuning from the MFA?
Thank you very much.