You could in theory just pay the fractional cost, but the enemies on the list are both not the same CR (even just regular skeleton and zombie) and several of them do not have standard monster entries so you'd have to construct them from scratch just to even start a comparison.
An alternative interpretation is that part of the process for making the original item, which is just a storage container, includes the cost of raising said 12 undead and simply having them and somehow subduing them would let you put a new one back in. Therefore, you only require the material component cost of the appropriate animate undead casting.