@Maraxus: I'm having problem with your multipliers. I'll attempt to do it here (with glyphed FS, assumed builds with Tundra Stalker and Unholy Blight and no Impurity).
FS = FS_base * 1.1 (Black Ice) * 1.15 (BotN) * 1.15 (TS) * 1.15 (BP) * 1.2 (GC) * 1.13 (EP)
FS_crit = FS * 2.45 * 1.03 (Meta)
DC_base = 443 + (0.15 * AP) (I hope this is what you meant)
DC = DC_base * 1.1 (Black Ice) * 1.15 (Morbidity) * 1.15 (Glyph) * 1.15 (TS) * 1.15 (BP) * 1.13 (EP) * 1.3 (UB)
DC_crit = DC * 2 * 1.03 (Meta)
Also DC crit chance will always be lower than FS because FS gets contributed by Agility, DC crit won't. Also, try 7000 AP which is currently the amount you get for raid buffs.
If you want to try Impurity, take out the 1.15 (TS) multiplier for DC calculation, and add 1.2 multiplier inside the parenthesis of DC_base calculation: DC_base = 443 + (0.15 * AP * 1.2)
Also, where does that 1.042 in FS calculation come from? I can understand the other parts where you assume that BotN is 10% instead of 15% etc. but I can't figure it out where 1.042 comes from.
*Edit: To calculate how much KM increases crit %, do the following:
- Calculate how much KM proc per minute (if instant strikes proc it too on MH then it's no longer 5ppm but more)
- Calculate how much FS you use per minute (based on rotation)
- Under ideal situation, assuming you can use KM proc in all frost strikes, calculate the ratio of FS with KM proc / total FS in % (=A%)
- Keep in mind that those crits coming from FS with KM proc could've critted on its own. To calculate that portions, multiply the A% found earlier with the % FS natural crit chance. Then take away that amount from the A% then you find the amount of % crit you get only from KM.
For example: KM proc 6ppm, FS use per minute = 15, so A% = 6/15 = 0.4 or 40%. % nature crit = 30% so we have the crit % of KM contribution:
0.4 - 0.4 * 0.3 = 0.28 or 28%
The total crit % shall be 58% or close to that amount.