File:Special Duration Up Chart.png

Formula
Bomb Rush, Bubbler, Inkzooka, Kraken: Duration (s) = [base duration] &times; (1 + (0.99 &times; A &minus; (0.09 &times; A)2 ) / 50)

Echolocator, Inkstrike, Killer Wail: Duration (s) = [base duration] &times; (1 + (0.99 &times; A &minus; (0.09 &times; A)2 ) / 75)

Note: Attack time for Inkstrike and Killer Wail does not change with Special Duration Up.