@PurpleBuz
Here, I'll fill you in.
The Apogee electric quantum meter is well known for having initial limitations, such as having spikes in the blue/green region of wavelengths, as well as not measuring wavelengths after 660nm. Apogee has long known of this ordeal and offers solutions, such as pinpointing the intensity of each wavelength found on the CCT graph for a given COB and calculating a correction factor for readings including wavelengths over 660nm. Obviously factored approximations from readings aren't the same as exact readings from the million dollar light measuring machines but we can use them to reliably determine how well one lighting source fares with another, whether it be a COB or a HID lamp.
Your observations are correct in that the lumen output/efficiency for cooler temperatures, such as 5000K, are better than warmer temperatures, such as 2700K, but what you fail to take into account is that warmer temperatures for Cree and Bridgelux COBs have a higher umol/PAR W conversion factor in comparison to the cooler temperatures. Don't believe me, ask
@alesh.
Based off both accurate calculations and readings/measurements, the photon output comes close to one another for Vero COBs between 3000~4000K, with 3000K sporting the highest amount of photons, which is what most of us and our plants are after.