I don't think there is any real disagreement here. Just a discussion about why the manufacturer might recommend that you wait X number of hours before switching over. I doubt doing it sooner will harm an engine. My opinion is, without any evidence to support it, that an engine probably does all the breaking in it is going to in the first 5 or 10 hours of operation.
You're right, all manufacturers have their own break in schedules. I also agree that most of the break in wear probably occurs in the first 5 to 10 hours.
My VW Jetta uses synthetic oil from the factory. Break in oil for first 5000 miles, they recommend not to change it early. then regular synthetic another change at 10000 and then every 10000 after that. I do a lot of freeway driving 5000 miles may be close to 100 hours fo use.
