No, you just noticed that now.
My usual way of playing is to get my players (not all the team, the basic squad), from 5* to 6* at the end of the season.
Next season, the same.
I like to keep my sp and play as a 5* team, at least untill the half of the season.
That way, I can see who of my players (or the whole team) perform good.
Then, I decide if I 'll make some changes or sell some players. Having an early 6* player it's hard to sell in the middle of the season (at least quickly).
This season (as previous seasons too, now with the new league draw), I 'm in a league full of teams 5&6* players so today I decided to give my saving sp to my players, so I can have some better chances for the league ( I 'm 2nd today, won the other 2nd - 3rd now).

So, after that prologue , this is the game I played earlier in the cup, before I sign the sp
Click image for larger version.  Name: cup 11-30 1st game.jpg  Views: 16  Size: 45.5 KB  ID: 58389

and this is the same game, after I sign the sp. The game shows the players with their current quality and stars
Click image for larger version.  Name: cup 11-30 1st game 6stars.jpg  Views: 16  Size: 46.3 KB  ID: 58390

* I should have sign those sp before that game - lol
anyway, I believe I 'll play better in the 2nd leg
(maybe because I wasn't watching the game)