A player needs a total of 75 points to go from star to the next, thats the basic rule.
If you have a striker thats on 38.8, 41, 40 for the 3 skill areas then that player is 1 skill point away from 40 quality and will gain a star, once that skill point is obtained the new star is given to the player and the player will be 75 points away from the next star.
36.8, 38.2, 37.6 would equal 36 points away from next star
38.4, 34.2, 33.8 would equal 68 points away from next star
38.0, 37.0, 44.0 would equal 5 points away from next star