Regarding the use of same system across several sizes of binocular, another member suggests the same hypothesis. That is a possibility.
regarding the article referenced note these quotes from the article, Marcus makes some good points, but,
The Nikon Multicoating is the best multicoating I have found in any comparable bino. You look into these lenses and you dont see them, it's like looking through air.
I've pointed this out before. Looking thru the lens tells you very little information about the coatings. You can do this with almost any multi-coated lens.
It is fully flat field, zero distortion, put an housecorner or electric cabel in the center and move towards the edge, the lines at the edge are as straight as in center.
What he describes, lines on edges straight as center, has NOTHING to do with flat field. He is describing a lack of pincushion distortion. So he has not provided ANYTHING that tells you whether or not it is flat field.
...with a little noticable chromatical aberation ( faint green-violet) on sharp corners.
Anyway I checked the power on night sky. Moon is nearly colorfree and racersharp , like looking with lower apo through an high quality ED- Apo.
Hmmm, my tests show false color equal to the Fujinon 16x70 and the much less expensive Oberwerk Ultra 15x70, especially on the Moon. It does not look anything like any Apo, or for that matter even like an ED semi-Apo. See my comparison in this thread to the WO22x70, which is labeled as Apo, but I've already noted in reviews (comparing to Tak 22x60) is not Apo.
The edge correction is not perfect , but still excellent, very similar to other such large high quality binoculars.
If the Fujinon would be considered a very similar large high quality binocular, the Nikon 18x70 does not match it for edge correction. Markus agrees with that.
I'd agree with the claims of razor sharp (on-axis) and high quality and edge correction not perfect. I'd disagree with his comments about flat field and chromatic aberration. The coatings are among the best, but Markus' example doesn't really support that.