Hi Der_Ryan_M!
Thanks for going into details!
So in this case (see picture below) my player will need to acquire additional 0,2 points (because right now he is 0,4 points short to gain the next star)?
That's completely right.
Is there a simple formula to convert the missing points into skills so that I will know how much I will have to train him? Or do I have to be quite careful and check after each training session? I know that Nik wrote a lot about that in his thread but I did not read everything and I'm still not very sure about that.
No, there is no formula. Just be careful when training. When my players are about 0.5 before the next star, I just go with a maximum of 6% condition loss into the training session, so for example 2x press the play for defensive players or 1x fast counter attacks and 1x pass, go and shoot for offensive players. When you are 0.3 and add a 6% training, there is usually no way he will get to the next star by accident.
Oh and just to be clear: I know the player is probably not very interesting because he is quite old but I just want to understand the whole mechanic and he is the only one who fits the best.
Edit: Well, I carefully trained him a few times and after three gained skill points (+3% skills) he is now -0,2 away from the next star. I can't lock him with another position or SA training because he is fully trained but basically I don't want/need to sell him. He's a backup player so it's alright.
What you should also notice, the % and the actual skill points are in no relation whatsoever. So a player can basically get no % in a training session but his skills can grow by 0.1 or more and vice versa. So just check after every session, not just the ones he gets %.