Question regarding breaking in a new 40hp Mercury

I've googled and searched this sub and I'm gonna ask, what is probably a stupid question. I'm a literalist and I need some guidance so I don't screw up my new motor.

Engine Break-In Procedure
IMPORTANT - Failure to follow the engine break-in procedures can result in poor performance throughout the life of the engine and can cause engine damage. Always follow break-in procedures

1. For the first hour of operation, run the engine at varied throttle settings up to 3500 RPM or at approximately half throttle.
2. For the second hour of operation, run the engine at varied throttle settings up to 4500 RPM or at three-quarters throttle, and during this period of time, run it at full throttle for approximately one minute every ten minutes.
3. For the next eight hours of operation, avoid continuous operation at full throttle for more than five minutes at a time.

When it says "run the engine at varied throttle settings...", how long should I keep it at the same throttle setting before changing it? 15 seconds, 30 seconds, a minute? They aren't saying that I continuously change the throttle like I'm using a hand pump, right?