I love fat quarters! That said, I too have encountered a problem with buying a fat quarter and not getting all the fabric I should. One year on a Shop Hop I bought all these amazing fat quarters from a store, something like 20 of them. I got them home and they were mainly 17x19. :shock: Now I refuse to buy fat quarters from them and I made sure to let ALL my friends know what happened. Let's just say that store wasn't happy because I even complained to the people who ran the Shop Hop. The store blamed the manufacturer & basically I was given an apology followed by them saying it wasn't their fault. Hm. Sure. Never is. :roll: If in doubt, I find it is easier just to open them up and measure them right there at the store. I don't always do it, because some stores never give me any problems and I trust them, but there are stores I make sure to do this at.
I have never purchased a kit so I don't know much about them. I would say it might be best to pull the fat quarters out and measure them. If they aren't correct, you can contact the manufacturer on the label and they should be able to make it right for you.