Star position is a very abstract concept, difficult for most people to comprehend; it refers to the quality of energy. The higher the star position, the higher the quality of energy. A difference of one or half a star may not seem significant, but once the gap reaches three or four stars, the power disparity becomes substantial.
Basically, when gaseous energy is compressed tenfold, it turns into a semi-liquid mist. Compressing the mist another tenfold produces a liquid. The power unleashed in different states is absolutely distinct.
If the energy of a Ten Stars bronze Black Whirlwind is considered equivalent to black gunpowder, then the energy of a Ten Stars silver Sandfire Dragon leader is like dynamite, with an absolutely different, and substantially larger, level of power.