If you destroy the Empress Dagger (by blowing it up with star force enhancement) to reset it to 0 stars, you'll gain around 8 more att if you star force the SW dagger after transposing.
(note: The Empress dagger has 208 att when the stars is removed, which mean 80 att come from scrolls, which mean it is not scrolled with +9 att scrolls or it was star forced too early, it is not a perfect weapon but pretty close to it, still a good value to transpose to SW if you don't want to spend money scrolling one yourself and then transposing)