GTIN (Global Trading Item Number) is a 14 digits UPC code with the package code as the first digits + 13 digits UPC code. For 12 digits UPC code, you will just add a leading zero to make it 13 digits. The package code will represent the number of inner box in a case. Typically, the inner box will be encoded with a UPC code (12 or 13 digits), and the outside box will be encoded with a GTIN (14 digits) base on the same UPC code.

But we have situation that our vendor does not implement GTIN correctly. Instead of using the same UPC code base on the inner box to create the GTIN on the outer case, they choose to implement with two different UPC codes for the inner box and outer case. That is to say, they treat the inner box and outer case as two different product. Then later on, they add the GTIN base on the outer case UPC code. I know this is not the right way to implement GTIN. However, our manufacturing is implementing their bar code this way. Is there anyway we can support both two different UPC codes for the same item with different packaging size? Can we support GTIN base on the 2nd UPC code, instead of base on the inner box UPC code?

Attached image is an example of how our vendor is implementing the GTIN. The label on the top is on the outer case. Then label on the bottom is on the inner box. As you can see, the inner box has a UPC code of 047700169804. Instead of creating GTIN base on this UPC code, they decided to assign a different UPC code to the outer case as 047700169811. Then they create the GTIN base on the UPC code on the outer case as 10047700169818.

At this moment, Elliott insist that since the UPC code for this item is 047700169804, so the GTIN must be derived from that UPC code and thus the GTIN will be something like 10047700169801. Can we do something about this? Ideally, Elliott should recognize both the 2nd UPC code on the outer case, as well as the GTIN base on the 2nd UPC code on the case. This way, it doesn't matter which bar code our users scan on the outer case, it will all work correctly.