Usually players work in the same way always... only the youngers of the academy can be really more effective if you powertrain them, and can be more efective with 5*-6*-7* in visible mode... so, with academy players you can see the differnece between 4*-6* for example... training them.
But with scouts is different, because the have 6* so, they are in good level to show you what can they do, so, if they are not effective, and do not appear in the matches with 6*, will be the same with 7* and 8* because there is a ratio of efectiveness in the programming of the players, "the level of stars" that a player need to have in some skills to work at 100%
I don't know if explain well,,, but.. what I've said, simply programming xD