Diary of a Wimpy Kid Book vs. Movie

 I've been a fan of Jeff Kinney's series Diary of a Wimpy Kid. I'm starting the movie right now, and I seem to see a trend: Not following the book.
Differences

• the book says Manny was potty training because of Greg's UNCLE that visited over a holiday
• the book says Rowley got to back from Australia, not Guatemala
• ok, they were playing flag/tackle football for PE, not "Gladiator"
• second, the reference to the restroom doors were a reference to the "no curtain shower stall" in The Last Straw (I think) about military school. the real restrooms had "paper-thin walls and every noise you make would be broadcasted into the whole room"
• the restroom was "wrong" because Greg started the rumor that the air fresheners were actually spy cameras, and nobody wanted to go to the bathrooms anymore (Second book, I think)
• Loded Diper van showed up in the second book
• Greg did not get busted for being in his brother's room until a second time. furthermore, he avoided it the first time by hiding underneath rodrick's bed.
• the second time, greg was in trouble for the same offense above, so that his mother made him get lessons for drumming (I don't know/remember what book it was)
• ok, it was a PE class of wrestling, not a club. It was after the football unit.

Ok, now I'm gonna stop because now you get the point. :)