she probably brought back the exact same design specifically to avoid having to pay the designer for a new valentine's design - that way, she can claim that she has to pay the designer, when in reality, she already paid for it, but has avoided reducing the price of the mugs - and actually increased it! - in order to pocket the extra profit to fund a tat haul.
that said, these "new" designs feature a slightly larger image than the original ones, and even with ste's extensive knowledge of excel, i very much doubt babs has any idea how to increase the size of a design without reducing the quality of the image, so she might have had to rope the designer in for a bit of help.