You can’t compare samples from two different planets. For just a simple example look at Exotic Earthyams. On Alcyon I’m able to gather over 200 in small area, i have 8 luck, and I’m getting mostly 2 yams per cacti. When I had also gathering epic, I believe I got exclusively 2 yams per cacti (but I did not record results, so can’t be sure I also since then i dropped the epic because I think it’s not worth it). On lower tier planets I don’t remember getting 2 Exotic Earthyams per cacti ever with a toon that has 8 luck. I may be mistaken, but… let’s look now at ores. From T4 I’m unable to produce more than 1 titanium ore per seam. Just can’t. On T5 I frequently get 2 per seam, and on T6 I get frequently 3 yams per seam. Another example is pulsating orbs, I do get 3 per fungi on T6 planets, but I don’t remember to get so much ever on T3 or lower tier planets. T4 and T5 just dont remember.
So in conclusion I think that drops per plant are limited on any given planet, but how much will drop MAX depends actually on tier of the planet. And with higher tier, gathering epic may be a good choice, but… to conclude test you just have to account for planet tier, and most of those test conducted i see don’t really say what methodology was used.