I don't think it would be confusing. If something is handmade from scratch, it should definitely cost more than something that's altered... at least that's my opinion. For example, I make journals... and the ones I purchased and altered them I sell for $8, while the price of the one that's handmade from scratch is $20. So, I think you can charge that $12 difference. And make sure to put in the description that the box was hand crafted :)