In Time or On Time - Confusing Phrases in English

source: Twominute English for lesson scripts and more learning.
# Explanation
--"in time":  It means that you are not too late to do something.
For example, yesterday I went to the movies with my girlfriend. The movie started at 4pm. We arrived a little late and missed the previews, but we were in time to watch the beginning of the movie.
--"on time":  It means that you are not early or late.
For example, I’m never late for work or class, I am always on time.
# Getting to Class.
Ron: Excuse me, Ms. Carter, may I come in?
Frances: Good morning, Ron. You are late again! Why can’t you arrive on time to class?
Ron: I’m sorry, but I depend on my father to bring me to school, and he is always late.
Frances: Well, Ron, tell your father that if you are not on time for the next class, I will have to call him to school and have a serious conversation with him.
Ron: Yes, Ms. Carter.
# Going to a Dinner Party.
Max: Hey, Kev. What’s up?
Kevin: Hey, Max! Why didn't you go to Sarah’s dinner party?
Max: I had to work until late…
Kevin: You missed it, man.
Max: What time did it start?
Kevin: Well, it started at 7pm, but I got there at 8:30.
Max: Oh, no! So, you missed dinner.
Kevin: Not really…I was late for the party, but I was in time for the dinner because they served it at 9pm.