Does a multi-position player perform better in a position more than another. I don't have a definite answer since I haven't thought this that much in the past, but in the case of Anton Selenkov i say definetley yes.
yea, well, more than this

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Neskens : bought as AMC only, very fast trainer which I gave MC & DMC positions + playmaker.
Usually playing as DMC and some times as my 3rd MC.
I use him in the corner kicks too.

Myths or facts ? :
- You can use any player in a different position from his initial and maybe perform better there
- A playmaker sa helps for corner kicks
- A high or low crossing skill has no effect at corners (the same for all the other skills - lol)
- There aren't good/bad players (if we judge from the rates).
I use Neskens as for C-K . He can give some assists so with that, he gets better rates.
If he was only a simple DMC , he wouldn't have so good rates.
That's why we cannot see if a defender (no kicker) is good or bad.