I heard that Japanese are very punctual on everything and one of the concerns my father had when I left to Japan was the cultural shock of me not being able to come on time -since I am Indonesian, I also am very well adapted to what we call "jam karet" which if literally translated means rubber watch, but what it actually means that on time for us can reach from half to one hour after the appointment-. So since my father had brought it up, it had also been one of my priority concerns. What I do now in Japan is I come to the lab everyday at 8 a.m -which is still very early in Japans lab standard- so in order to do so I put my alarm off at 5 a.m -so I can`t be late. But in my experience with several young Japanese, they are not as punctual as they are myth to be - its either that or my German upbringing which came to surface lately and forces me to come to an appointment 15 minutes earlier is the real problem - but point taken, they are not that punctual in informal appointments.
As for the formal ones, I have no experience of yet. I will inform you later on of course, because you must understand how time works where ever you live - or you are simply doomed.