Mythbusters of top eleven

[Cloverfield]

all dc/dmc players perform better in dmc position.

It is not up to the player, it is due to the position itself.
DMC is involved in many aspects of the game, marking, passing, shooting, so his rating can easily be great.
The only time I see dmc completely failing having a bad rating is when he is outclassed by an amc..

On the other hand DCs (when they do not score) they have low rating, you may win, all your team be 7,5+ but yet DCs can stick around 6,5.

[KenoticFC]

all dc/dmc players perform better in dmc position.

It is not up to the player, it is due to the position itself.
DMC is involved in many aspects of the game, marking, passing, shooting, so his rating can easily be great.
The only time I see dmc completely failing having a bad rating is when he is outclassed by an amc..

On the other hand DCs (when they do not score) they have low rating, you may win, all your team be 7,5+ but yet DCs can stick around 6,5.

That's not the case with me. I'm currently using a formation with 2 DMC's and they rarely score yet they have high ratings usually. When they are not performing good I usually swap one for a CM. In his case today the other DC was having a fantastic match with an 8.6 rating (no goal or assist). The same I tend to see with a AML ML AMC player. He usually plays better as an AMC.
I agree with your point that DMC get more involved. So many times during matches you dominate the GK and the defenders will have lower ratings (because they didn't gave to do anything).
I still think this is an interesting factor to look for.