You're right, but I think Spathion and Paramerion are like slower, stronger knightly weapons. Even if it's only 2cm or so, I think of them in a different tier of length to the arabian cav sword.
Arabian cav sword is 105 length and 95 speed. 94-95 speed and 31-32 cut would make them good weapons in that long niche category, but they'd still inferior to the arabian cav sword as a pure 1h. The tradeoff would make sense assuming the prices increase on the weapons.