I 'm saying that if my players have good or very good morale, I never give them boosters.
Exception is my CH.L. & Cup finals.
There, I give from "good" to "superb" with a double boosters.
I don't believe that it makes any serious difference, just do that because if I 'll loose, I would be thinking ****, I had to boost my moral to max
If my players have poor, very poor only then I give a double booster.
not that I expect to increase their performance but I observed some times that players with very low morale , are vulnerable to injuries or missing penalties and F-K.
With this way, I have the number of packs you can see in my two teams (and don't know what to do with them)
* never farmed or bought any blues .
So as Mourinho saying when the game is loading, morale boosters are to increase the morale of your players but he isn't saying that with full morale your players will perform better
* agree with Jeeves about morale packs
** also agree with Jeeves and others. Win bonus doesn't increase morale.
Better play a couple of easy friendlies (to get some extra money too).