Akali's movement speed and max W bonus is wrong

Akali's base movement speed is 345. When using her max W the movement bonus is 40%. 345*0.40=138.

Add that to 345 and you get 483.

Correct me if I'm wrong, please.

In practice tool, when maxing her W it still says 40%, ok.

It says her bonus from the 40% is 124 and the total is 469.

124 is 40% of 310, not 345.

124 would be 36% of 345. Is this a future patch or a bug?

What's weird is that Celerity's bonus applies to the correct number not the visual number, so perhaps it's the displayed number that's incorrect not the actual movement speed itself.