My thoughts are he his taking measurements off the screen which is fine, but to translate it into lumens we need to know the size of the screen. I didn't see it in the review but I know it isn't anywhere close too 216" for the type of screen being used and the settings used on the projector. If it is the screen mentioned in his other review of the Mitsubishi 8000 he is using a 92" screen and that would seem on par for the measurements.
If I calculate for a 92" 1.0 gain screen (The Carada isn't a 1.4 gain screen with real measurements, closer to a 1.0) the projector is putting out about 650 lumens in natural mode and on the economy bulb setting. This sounds a little low but might be correct if the projector is placed farther from the screen within its the zoom range or depending on the age of the bulb which isn't stated in the review.
In general most companies have inflated specs and use various techniques to get them and rarely publish figures on how the equipment is likely to be set up. An industry professional once told us in a class "The only specs I trust from a manufacturer are size and weight, the rest is marketing." This is pretty much true in most cases and with projectors unrealistic lumens and contrast figures are common.