As I said, I've noticed the same thing this year and in the last two FIFA releases, which is partly why I as well rarely play anything except exhibition matches. I play on Pro and have low-scoring, even matches. I doubt I've seen the CPU score more than twice in the first half -- it's usually back-and-forth until someone scores later into the game.
Last night I started up a new EPL tournament. My first match was against Blackburn. They scored on a header in the first 5 minutes. Intrigued, I reloaded the tournament and restarted the game. They scored again on a header in the first 5 minutes. Altogether, I restarted the game 6 times: they scored in the first 5 minutes in every game, 5 times on headers.
This morning, I created a new EPL tournament and tried the test again. Everton was my first opponent. Guess what? In the 2 games I've played, they scored on a header in the first 5 minutes.
The game programmed to, at certain times, give you a greater challenge in tournaments and season play. CPU players get attribute boosts, and are suddenly more agile and more deadly with crosses and headers. But I don't know how much of this is specifically related to the custom tactics versus simple ratings boosts for players, so I'll stay out of that argument.