I did the same thing I always do on a new engine...Load it as hard as possible, and drive it like I intend to use it (after it is at operating temp of course...). This practice has never left me stranded with a bottom end failure in 12 cars and 700,000+ miles. I have read the same haynes manual - it is ok advice, though I just do things this way as I have seen many engines running on a dynomometer after a fresh build at full load - and watched the crankcase pressure go down and down as the rings seat, conversly I have seen engines that were dyno'ed at a later date (after insufficient break-in) to find that the rings will rarely ever seat (and keep the same relative crankcase pressures) as an engine that was properly loaded initially.

BTW: I have 10,000 miles in 6 months on the X an it burns no oil, has great power, and overall runs like a champ...as well following only the Nissan service oil change guidelines.