Maintenance penalty

Ok so I know there is a penalty for having more than 3 types of aircraft family in your fleet. My question is, if I had 4 types now (so the penalty is in place) but a month later I have gotten back to 3 types. Do I still have the penalty ? 

No, you won't.

Cheers. Simple to the point :) 

I read somewhere that the penalty is a 15% surcharge. Will that apply to the total maintenance cost (=all types) or just those in excess of 3?

The penalty applies to all maintenance costs