These values are based off the partially implemented values that went up on Test day 1 with as global profession based proc rate.
Over the past few days on Test we have changed it to a recipe based proc rate, so baseline recipes within a profession can have different proc rates, and we have been tuning the rates / finding recipes we missed with each Test update. (Ideally on vessels now you should see a 1 in 7ish rate)
As you craft more within a profession you will see more souls, those can be used to upgrade disciplines or upgrade belts.
The goal with this was to match the gameplay to the activity type to the advancement model; ie crafting gives you crafting advancement, harvesting gives you exploration advancement, combat gives you combat advancement. Once we have the proc rates tuned, it should just feel every few end item crafts you get a soul.
Which leads into...
The Belts stats are still in flux and have a quality upgrade path as well based on souls, which lets you choose between upgrading disciplines / belts. More than likely we won't enable the Belt uprade recipe until 6.300 however.