i read that UVB is detrimental and we should use UVA instead.
https://www.blackdogled.com/blogwhich-is-better-uva-or-uvb/
But it is the UVB radiation that significantly prolongs the active ingredients. UVA will only change / improve the terpene profiles, antioxidants and so on, but the effect on the active ingredients is not that strong as they claim. The reason for their claim could be that UVA diodes are widely available but UVB is not. Today there are very few UVB diodes and they are expensive and not powerful enough.
If plants eg. grow at 2000m, UVA and UVB levels are increased, not only UVA. The same applies to equator height, since the distance to the sun is also reduced.
In fact, even fiber hemp plants can re-form active agents when exposed to increased UV radiation. Take a europian fiber strain eg. to Jamaica and raise it for several generations. You will find that this 0,1% thc strain will suddenly become active again and get better and better with each generation.
I'm pretty sure this is because of the enviromental changes and mainly because of the UV radiation.
Remember, a few of the most potent strains are located to the mentioned regions where the plants gets increased UVA and B levels.
It is obvious that the plant protects itself with increased resin formation from the increased UVA/B radiation, as the latter can damage the genetic material (DNA). To trigger this self-protection, we need the "harmful" UVB radiation, IMO.
In fact, the level of a reptile tube is not as damaging to plants because it immitates conditions in deserts or jungle regions ( with 10% or 5% UVB). Even the tube manufacturers claim that the plants in the terrarium will be not damaged.
Another big LED manufacturer claims to achieve the same effect by using an extra week with only pure blue light (youtube vids).
Possible that also has a certain effect, but for really significant increases, it also needs a bit UVB in my opinion. The latest pontoons from Indagrow also have UVB-tubes(2x 54w for a 4x 4'), but use LED's for the rest of the spectrum. I think the guys from Blackdog do their claims, because it's much cheaper to just integrate UVA diodes.