Would the smaller ones be the same size as the larger with one more later of hexagons going around? Maybe the larger ones are for setting the blocks together and after you attach a smaller one, centered on one side, you add the other 5 sides onto the smaller block, making it the same size as the larger one. Without seeing the blocks, I'm not sure what else might be going on. You could post a picture of the blocks side by side so we can see what you mean.