CVS - duplicate item numbers with different deals for the same UPC

I want to buy six of this item. In store the price is $6.79, and if I buy six, I hit the "spend $30/get $10" ECB, and I only pay for three because of the BOGO, so my net is around $10. (As far as I know?)

The problem, though, is that this item is the exact same UPC (I went and looked at both items in store), but has a different deal ($4 ECB for buying two, this is not BOGO). The price is still $6.79 in store.

How do I know which one applies if I scan at the register, without actually paying for the items?

Thank you!