File:Special Charge Up Chart.png

Formula
Points to Charge Special Weapon = [base points to charge]/(1+((0.99x-(0.09x)^2)/100))

Base points to charge:
 * Inkzooka: 220p
 * Echolocator & Kraken: 200p
 * Bomb Rush & Bubbler & Inkstrike: 180p
 * Killer Wail: 160p