Is Sale Star working properly?

Hey all! Just trying to figure this out since I didn't see anything just yet about this item. My daughter and I were playing with new items and she found the Sale Star. On initial use, it's pretty neat, but she got a second one and we were theorizing if it would give more items per star or have a chance to up rarity like Shipping Request Form does on stacking. So far we didn't notice any changes, but if anyone has some insight or can tell me if it's only worth just having one I would appreciate it!