My calculator does handle true speeds.
Don't know what true speed is?
If you don't know what true speeds are, it happens when you're using speed sets on someone.
The 12% increase will add a decimal, eg. 98 speed on Maneater goes to 109.76 but it'll show 110 ingame.
These speeds are used for the calculation of the turnmeter in game but not shown.
If you're going 4 turns to every 3 turn the clan boss takes, you sometimes have very little leeway on the speeds,
and then truespeeds can become an issue. Let's say the "Range" tells you, you have to be between 241 and 241,
then that 0,5 speed difference from what's shown ingame and what's actually the number can make a difference.
The mastery called Lore of Steel which increases the bonus of speed sets by 15% making it 13.8% makes this issue even worse.
In my experience you'll have alot less true speed issues without Lore of Steel.
All Speed Buffs
Notice you cannot use Lasting Gifts Mastery or the prediction will be incorrect.
If there's a 30% chance you'll get 3 round buffs instead of 2 round buffs, it'll be impossible to predict.
So it's assuming that you don't have that mastery.
Setup for Ma'Shalled
How often = 2 (it's on a 3 turn cooldown but he takes an extra turn immediately which makes it go down to 2)
Check Is Ma'Shalled (he looses 1 turn of his own speed buff immediately when he takes his extra turn, so he gets 1 turn speed buff and everyone else gets 2)