Problem saving UPC/Barcodes to specific products

[PRbyIrinaB]

I just started using Shopify and am trying to set everything up. I have my products uploaded but decided I want to start using a UPC/Barcode for each product (I resell so the products already have a UPC code on them) at checkout to see if it makes it easier for myself. I also thought it would kill two birds with one stone when inputting inventory. However, for some reason, the UPC/Barcode isn't saving into the product. Here are the steps I'm taking:

1. Shopify App > Product Page

2. Inventory Scanner > scan the UPC code

3. Choose the product name

4. If adding more than 1 of the product I click the inventory number, select the correct #, click the checkmark/save, then apply changes.

I get a changes have been applied message however when I am reviewing my product later I see the inventory count saved correctly but the UPC/Barcode didn't save to the product. Why?

Help!