Here's everything I've seen in KOMBI so far that appears to be referring to "corrections":
- C0A_BBV_KORR_HA
- C0A_BBV_KORR_VA
- BC_V_KORREKTUR
- BC_DIGITAL_V_KORREKTUR
- UNTER_KORREKT_WERT_1
We know that BC_DIGITAL_V_KORREKTUR fixes the digital speed readout. One would think that BC_V_KORREKTUR would be responsible for analog speed readout, but I've heard it doesn't have an effect (perhaps there's another value that needs to be changed as well). I have no idea what the BBV HA and VA corrections are.
The one that catches my eye is UNTER_KORREKT_WERT_1 (German for under correct). There's a few different values available to play with. Might be worth fiddling with.