Cannith Crafting level progression

Level Progression (Post-Update 11)
Experience needed to advance in Cannith Crafting system is reduced with Update 11. Players that had leveled before may find their crafting levels increased. Post from Eladrin

Level Progression (Pre-Update 11)
Levels beyond 39 seem to require 'Next Level' * 10 XP to gain the new level. This is certainly true up to level 50.



Experience From Recipes
First of all, some definitions:


 * CraftingLevel: your current crafting level
 * BaseLevel: it's level as displayed in the crafting device for a given recipe
 * EffectiveLevel: BaseLevel - [the number of times it has been successfully crafted]
 * SuccessRate: the (calculated) basic chance of crafting a given recipe
 * LevelGap: = EffectiveLevel - CraftingLevel (can be negative or positive)

For a recipe where LevelGap >= 0 (but no more than 19):


 * SuccessRate = (20 - LevelGap) / 20
 * XP = EffectiveLevel / SuccessRate


 * This matches the observed values exacly.

For a recipe where EffectiveLevel < CraftingLevel (but no more than 10 below), I do not have it exactly correct, but it is extremely good approximation:


 * SuccessRate = 1
 * XP = EffectiveLevel * (1 + LevelGap / 10)


 * This seems to be very close to the entire set of rules; the calculations for when EffectiveLevel < CraftingLevel are not exact; this results in some small variation from observed values (typically my estimate can be 1 less than the real values, but afaict it is not a simple rounding error).


 * Diminished Returns: When crafting the same recipe multiple times, you will gain ~10% less XP per shard crafted after the first and will have a extra 5% chance to craft it. (12 XP first craft, 11 XP second craft, 10 XP third craft, etc) This decrease does not always properly update on the crafting UI (when it gives 0xp it will not even tell you, and keeps the last known value). There has been no confirmation on whether this is a bug, or Working as Intended.

Experience From Deconstructing
Material level * 1xp, in the school of the enhancement you're deconstructing. Does not apply to shards or crafted items.