I'm very happy to see that someone else has taken the initiative to investigate the legitimacy of calculated data and compare it with real world numbers. That is science at it's absolute best and something that I find highly honorable.
My data taken from an Apogee PAR meter, which I take seriously and enthusiastically, shares similarities with your data, in that the difference in output between a Vero 29 and a top-bin Cree CXB3070/3590 is not as great as what we've been led to believe from our trusty datasheets.
Now before I went on hiatus a few months back, I sprung some data on you all on how these cobs compared against one another and much to my surprise, the Cree cobs DID NOT perform as greatly as expected when compared to their Vero counterparts. My final conclusions at that time were that either Cree was giving us exaggerated projections, Bridgelux was giving us deflated projections, the Cree COBS from Jerry were NOT genuinely binned as advertised, or that somewhere along the lines I goofed up and made considerable errors. Since then I've compared all of my data, plus some with the latest Mothership, and it's now evident through what you've provided, Robinccn, that there's something off with these Cree cobs that most, if not all of us are obtaining through Jerry Kingbrite.
I suspect ordering straight from Cree would serve as a hopeful yet costly attempt at restoring faith to the Cree CXB namesake but how practical is that for the DIY squad? And how do we, as consumers, differentiate between Jerry and other dealers of Cree cobs?
As far as the sphere test goes, I really don't see how taking that route is going to change anything that has already been established mainly because if someone has a PAR meter that measures X to Y wavelengths and also have a correction factor that takes into account W to X and Y to Z wavelengths, then it's simply a matter of light output and determining which lighting source puts more of it out. I'd suspect the blend of spectral discharge would vary between the Cree and Vero cobs, as well as between two of the same kind, but that's not something a bunch of us find indicative at this time when choosing between the two considering both cobs have similar spectral charts and are obviously kicking ass in the grow scene.
In conclusion, I'd like to see an in-depth analysis of how a low-bin Cree CXB3590/3070 cob fairs against a top-bin Cree CXB3590/3070 cob. If those numbers are similar, then it's should be apparent to all that someone or something is falsely advertising their product.