This practice exploits a major flaw in the game. It's not just about passing the level players, but the attributes with negative values presented as 1%.
When a player has a 1% attribute and he passes the level through negotiation or advances a season, visually that number does not reduce, but for the calculations of quality of the players are used negative values and that drastically reduce the quality of the players.

See the following example of its effects with a TOP 1 player. The print is in Portuguese, but I believe that the attributes are in the same positions in all languages.

Player
Click image for larger version.  Name: Sem título1.jpg  Views: 194  Size: 53.2 KB  ID: 100703

1- Quality of the player attributed by Nordeus
Click image for larger version.  Name: status1.png  Views: 184  Size: 15.4 KB  ID: 100705

2 - Quality of the player calculated based on the means determined by Nordeus
Click image for larger version.  Name: status2.png  Views: 173  Size: 16.9 KB  ID: 100707

3- Player quality calculated with math
Click image for larger version.  Name: status3.png  Views: 176  Size: 15.7 KB  ID: 100709


Here is the link for visualization with the calculations: https://docs.google.com/spreadsheets...it?usp=sharing

Now, was changing training really a priority to eliminate mutants?