coach report of player gives a different potential ability from time to time

[krenault35]

hi, Im playing as Man U for the second year and i notice that some of my player (noticeably Rafael) have different potential ability given by my assistant manager and coach. Sometimes its 3 and sometimes its 3.5. And its not just because the assistant manager has bad attributes because my other coach with good attributes ( 17+ judging PA, judging CA, motivation, discipline, determination, tactical knowledge) also give him a 3.5 one time, then 3 at another time.

Isn't Potential ability set once you begin the game? How does coach/assmanager report on individual player works?

Thanks in advance for any solution