S950 - Filter effect varies between keygroups

So i fount a record that had a sample I chopped as an mp3 like 4 years back and felt like redoing it.

It had drums on it so i lowpassed it to get rid of the hihat but heres the problem.

I set all my keygroups filter level to 65, but its not working properly. Some of the keygroups are getting filtered a lot and some close to none, what am I doing wrong?

There are some parameter that control the FILTER parameter. I would check if they are on the same value for all keygroups.

1. PAGE09: VCF ENV ADSR & amount
2. PAGE11: Velocity to filter parameter (the higher the velocity the more open the filter)
3. PAGE15: Key-filter (the lower the key, the more open the filter AFAIK)

peace