Are there diminishing returns or some kind of soft cap on the Gathering stat?

I've been slowly gearing up my miner through Red Scrips. It's a bit of a slog, yes, but it'll get me to a good place, where I'll be able to supply myself anything I need for ARM and BSM (until I need cloth or leather...I digress). I've also been making good amounts of Gil farming Adamantite Ore, but have had that 5% miss chance hit me more frequently than I'd like.

I've been saving red tokens for a couple weeks now, and yesterday was finally able to buy the 180 chest (which was a huge jump over the 130 blue scrip chest I was using to get by). Port back to Helix, wait for the next spawn of Adamantite, aaaaand...I'm still at only 95%. +30 Gathering over my old chest, and I'm still at 95%. It's a little frustrating, to say the least, when I was able to get 100% gathering unbuffed on at-level nodes while I was leveling up.

Is there a cap specific to unspoiled nodes that prevents a native gathering rate higher than 95% (I'm pretty sure there's something like that for Perception)? Is my only way to get 100% collection rate to spend 50GP every time?