Might be that aerials score more but not sure. My previous high scoring defender was a DC who was a PK specialist who one season, 6 seasons ago I think, scored a lot of other goals too. I remember a CL semifinal where he took me to the final in the 2nd leg with a hat trick including only one PK goal.

Since making this post my DMC who doesn't even feature that frequently anymore has been my surprise goal machine. 14/6 this season, most goals coming in the recent games. Prior to this season 193/10.