training a player to 172% doesn't make him perform better than if he was 140/150%. the only benefit you gain from 172% is the fact that you are a season or 2 ahead with training. i maintain my aml and amr to finish on 180% at the end of every season so it guarantees them a long playing career.
others factors to take into account are that perhaps your opponents ST plays alone upfront in a 451 formation without wingers so it's normal he gets the majority of the clubs goals whereas perhaps you play 433 so your ST plays alongside an AML and AMR so club goals are more shared out.
On the contrary, my opponent played 4-1-2-3, and I play with one ST.
The fact that 172 is not better than 140 is unfair. Reaching 160% is much harder and requires more resources. Ok, if there is no difference, then there is no point in pumping above 140%.
If the game "decided" that you will lose, you will lose.
Sorry for the English. This is google translate.