Good luck. The matte is actually the clear coat, not the color coat. At least that is my experience. One thing I don't like about matte paint (I really love matte paint) is the difficulty in restoring it after a chip or scratch. You can't just buff it out.
Well this is what I came up with. Mixed some grey and black up
This is a lighter shade that matches in one light but not the other
And a darker shade which is also the same effect. Matches on one light not the other.
Stupid matte grey