11. New Forge mechanics: to create an item of a level higher than the character’s level, you must have the previous level item of the same type. For example: players cannot craft Heavy Pauldrons until they have crafted Medium Pauldrons.
Current characters will receive access to all items of the level they are on, regardless of items crafted before.Thats why he can craft the items without the one before that.
When you destroy an item you get 50% of the needed ressources back, rounding up on uneven numbers.
That means: When you already invested more than 50%, lets say 60%, and only need to invest 40% I advise you to craft on and get the 50% back which leaves you with 10% more as when you realized your mistake.
When you invested less than 50% I advise you to try to forget your mistake
Once you crafted the higher level item the other item is hidden automatically on the list and you don't have to look at it any longer.