When I bought my Fiesta in 1978, there was an initial short break-in period for the engine of 300 miles, after which you had the oil changed and a number of things checked and tightened. But that was in the days when engines wore out in 60,000 miles or even less (though mine went 190,000 before my sister's boyfriend totaled the car). The oil in the car as delivered new nowadays is the same that they will put in at every oil change. There's no such thing as break-in oil any more (even in the old days it was the same oil you used later).
The idea of varying speed is meant to allow the rings to seat, which will lead to less oil consumption later in life, and better compression later. It's the acceleration which seats the rings.
If you've ever raced dirtbikes, you know the procedure, as it's still practiced on them.