Nono... do not confuse the "attendance possesion bonus" that is a +5% and +8 if you attend (with full stadium)**
and the "training bonus" that you have to activate that do not give a +5% (10% to15%) because it doesn't work like this, these bonuses, "activate a BP in certain players, not in all", so it is not = a +5% BP exactly.
You can see it for example by pushing the condition bonus during a whole match, and another match without. You'll notice that "some players, 4-5 now not sure but I tested it, lose less condition than the others.
But these training bonuses are selective, not applied to all team. And the 4 work in the same way.
...and well... I think I solved part of the main topic of this thread xD