Pls @Meddler, Can you explain me this thing about Yasuo's q?

Base cd on Yasuo's q is about 4 sec, ok This ability doesn't scales with cd but with attack speed, ok So why can it reach 1.33 sec of cooldown without not even 2.00 of attack speed? And Then a reduction of 2.77 sec isn't 40 % of 4 sec, so Why Has yasuo more then 40% CDR on his Q? He has no mana, he can ult with every single knock back/up of this game, he really need to have more then 40% cdr on ability which scales with an offensive statistic rather then cdr? Sometimes you need to sacrifice some damage to have a better cdr on your ability, this reasoning does not apply to Yasuo and I'm curious if there is a particular reason. Thank you for your attention and your time