I think when a chip is not made "correctly" - that is, not as intended, it is an error chip, not a variation. That is only a label, not an indication of value. Other factors such as rarity and collectability dictate value. For example, The Four Queens halloween 2000 has no denomination on one side, yet all of the chips were made that way. It may be an "error" but it is not "rare." If one sample chip was made with denominations on both sides, THAT chip would be valuable!

As to the error you describe, I think it is significant, and an interesting, collectable chip, but not a "variation." Any more than one chip coin aligned in a batch of medal aligned chips would be a variation.