Sometimes the stats on gear are going to be vastly different from one another, the displayed stats, and the maximum values of stats allowed for a piece of gear. Like you noted with the difference in the Gathering stat on the Gaganaskin Gloves of Gathering” versus the “Bloodhempen Trousers of Gathering”, if we look at the current end-game crafted gathering gear (i320 Ala Mhigan gathering set), we see the following values on those gloves versus the legs:

Ala Mhigan Gloves of Gathering:
GP: 5; max: 6
Gathering: 163 (185); max: 218
Perception: 0; max: 15

Ala Mhigan Bottoms of Gathering:
GP: 5; max: 6
Gathering: 109 (123); max 145
Perception: 11 (12); max 15

There’s a vast difference in the maximum gathering allowed for the gloves and the pants, but the maximum amount of GP and perception allowed per piece is the same. This is just the way the gear is designed and implemented in the system. Sometimes the weight of a piece varies between the different jobs; it’s my understanding that DoW/DoM place a lot of emphasis on body/legs for gear, but that may not always be the case for the DoH/DoL since they function differently in the game.

I’ve also heard that the developers use a sort of randomizer when determining the stats of pieces of gear, but I cannot attest to how accurate that statement is.