good people of the gameplay and balance, i require your assistance!

Nautilus W deals 40% AP over 2 seconds, making it deal 20% each second.

but my question is, what if his AS exceeds one second?

for example a Nautilus with 2.5 attack speed, will he Deal 100% AP? (40% on his first attack, another 40% on his second attack, and then a 20% of his first tick on his third attack [the .5 AS part]

OR

will he deal 20% AP Each attack, because he will be constantly refreshing the attack, causing the second tick to never count?

and if the latter, what is the IDEAL AS i should stick with to land Fast Auto attacks, while still applying the second tick?