As I understand it, there's a cap on how much experience you can gain from deconstructing jewelry when your skill is at a certain level. For example, at skill 10 you will get less experience from deconstructing CP 160 jewelry than you will at skill 30. This means if you are trying to deconstruct intricate jewelry when your skill is still low, you will hit the maximum possible experience quickly and not get anything extra for it. You need to save it for when your skill is higher already.

That said, if others who know more about this than I do could confirm, that would be great. This isn't something I've tested extensively personally.

When you are at lvl 14 in jewelery crafting you get less inspiration (crafting exp) for deconstructing cp 160 jewelery then when you are on lvl 30. But I tested it and you get the same amount of inspiraton for deconstructing intricate jewelery as for normal jewelery on levels between 12-30 (don't know about levels above that). I'm certain this is a bug, only existing while leveling jewelery crafting, blacksmithing for example works correctly