Sorry Dude, I have been tied up and haven't looked at this thread in a while.
The name of the manual is Honda Fit Owner's Manual. I have an '07 but I assume it's in the '08 manual too. I could be wrong. Page number, I don't know. It's under the oil change or break-in category, one or the other.
And of course I don't know the guy who wrote it, but it just stands to reason that a call like that could only be made by the engineering guys.

Engine and oil technology has gotten to the point that longer intervals are OK. See BobIsTheOilGuy.com for better explanations than I can offer.

Seems to me that conventional wisdom doesn't always hold true, what with the tighter tolerances and greater pool of research that the guys have to draw from. I never would have thought that such a small, high-revving engine would use such light, thin oil, either, but that's what it uses due to the 12-micron gap at the cylinder walls, from what a friend who works in the Honda engine plant in Lincoln, AL told me. I trust Honda's recommendations, mainly because I know they're very meticulous, researching a lot more thoroughly than almost any other company.
Of course, the Challenger astronauts trusted Morton Thiokol for similar reasons. Only time will tell what turns out to be the best course of action.

 

Wait until 15 percent or even lower is fine. The old "every 3000 miles" is BS. You can safely wait 7,500 miles before changing. Just go by the maintenance minder and save yourself some $$.