Why 100 rated players have 20% goal conversion rate?

[twoplustwo]

I don't know if this is related to the tactics section or not.
I play 433 PW pressure, mentality, tempo all above 70.
All my players are much much better than opponent: 100+rated.
But there are a lot of games when I shoot 18 and score 2 or 3 goals.
Ratings doesn't seem to affect this. Even If I have slightly stronger team, and when I have much much stronger team it still remains the same.
Is it tactics related or engine prevents us to score unrealistic amount of goals?

[DE XRIST]

@twoplustwo
Tactics and only tactics.....many shoots doesn't mean that all of them will be goals....this is what happens in real life too...and to prove you that you can score many goals, that a look..