Players Level Up and Playing Positioning / SE

[Mak112]

Guyz is it true that if I have a player only dedicated with one playing position only will train fast.
But if I have a player having two playing positions then his advancement from one star to another slows down.
And If I have a player with three playing positions then it further slows down.

Same for special ability, Is there any help material available in this forum regarding positions and SE affects players level up.

What do you think about a player having one playing position with one or two Special abilities is better or three playing positions and Special ability is better (depending on the fast training)
Thank you.