I have done the latter, since the math is pretty straightforward. I do wonder how they calculate those initial figures. Seeing that we are placing most of the material in those several feet (width) of banding in the dripline zone, it would be more concentrated on a per tree basis ( most folks are not dumping much in the inner zone or isles in most orchards usually). Those published figures are for every square inch of orchard broadcasted. As a contrast, however, I am of the opinion that most of that soil matrix is going to be filled with roots (disregarding concentrations of feeder roots for the moment), so particularly those isles may find benefit. In a babied (dripline irrigated and fertilized) high density system the root reach is greatly limited, so indeed fertilizing those outlying areas may be wasteful, but with more vigorous systems the roots are going to colonized the entire orchard, and some of the neighbors as well. In fact, we do most of our "fertilizing" in the median space between the trees (a good deal of which is in that dripline sweet spot), and more concentrated. Perhaps, however, fertilizing areas like pathways and other tangents, adds to a robust overall system, useful in reducing erosion, keeping nutrients cycling (dynamic accumulators and the like), and producing a crop of mulch material. These need to eat as well. As an aside, we have bent the farm toward coarse organic materials (mostly generated onsite), and away from traditional granulated fertilizers (in large part) since the former is a slow release, sustainable approach and the latter is a continual spoon feeding cycle we are trying to avoid. So, an initial or very occasional big slug of nutrients is very useful in depleted landscapes, they should be used to usher in or maintain a more natural and self supporting ecology.
Walden Heights Nursery & OrchardZone 3 in Vermont