Most gathering nodes have a finite limit of the number of items you can gain from them. There are some nodes that are unlimited, but those nodes tend to provide very common items, like Frogs or Worms. The rest vary the number of times, and is unique to the node itself. Each node has a minimum and maximum number of times you can gather from it, and is set when it spawns.
What the Gathering skill does is that it skew that random number. Gathering-1 weights it towards the minimum limit, and Gathering+1 and +2 send it upwards, to it's maximum. It doesn't increase the limit, it just weights the randomness in your favor. For nodes that have only a set number of gather attempts, the Gathering skill is entirely useless.
Reading that blog entry, it sounds like the author is unsure of what the skill does, and thinks it increases the maximum number of times you can gather from nodes. If the node in question has a range of gather attempts, Gathering will bump it upwards, but it won't increase it beyond the node's natural gather limits.
I have tested this in the Deserted Islands, Freehunt. My target Area was Area 7, due to there being three fixed nodes: Grass, a stone, and mushrooms. Sometimes, there's even a mining node.
I made a dozen runs, three each at:
- No gathering skill
- Gathering + 1
- Gathering + 2
- Gathering + 2 & Felyne Gatherer (I used Gourmet Vouchers to guarantee the skill)
The Brady Guide lists the maximums of these nodes as:
- Grass: 10
- Stone: 4
- Mushrooms: 3
- Mine: 3 (There's two different nodes, but one is fixed at 3, and the other has a maximum of 3, so they're the same, regardless)
Here are my averages:
None +1 +2 +2 & FG
Grass 7.67 10 10 10
Stone 4 4 4 4
Mushrooms 3 3 3 3
Mine 2.67 2 2 2
The mine average is lower because it's not a fixed spawn; there is a chance to have no node at all, and somehow, each one group of runs with a skill had one single run where it didn't spawn. Runs #5, 9, and 11 each didn't have a mining node.
Based on this data, I can say conclusively, that the Gather skills do not increase the maximum gather limits; they just ensure you have a better chance of gathering everything from that node. If it increased the maximum, at least a single run would have gone beyond the maximum limits.