40 miles? I don't think it matters who is correct on waiting or not waiting to change to syn at 1k miles, 40 miles is, well, its 40 miles.

My current bike was Dynoed with 10 miles on it running HD360 dinosaur oil. Change to a full syn (Amsoil) at 150 miles, 500 & 1,000 and then every 2,500 or so from then on. I have 20k miles on it and it runs strong and has not used a drop of oil and it has been run in what would be considered severe conditions.

Same thing on previous bike except it was a BB kit that was broken in on a Dyno this time with syn in it and changed as above.

Ditto on CVOs coming stock with syn, as well as a number of high performance cars.