Yeah I think that's what he meant, e.g. include zeroes in the avg. Which would explain the high #'s you see from Garmin.
Are those high numbers from a Garmin app or the device? My 705 shows high numbers for peak power, and it's usually closer to my 5-sec power since it's doing 3-sec averaging. Kind of confusing but fun since I know I did better than what it says (peak-wise anyway).