Increased spell damage working incorrectly?

I've been trying to figure out how to calculate spell DPS (including crit) and -in playing around with a low level character for this purpose- have become even more confused. Can anyone clarify? Here's what I'm wondering about:

Templar with no skills allocated in the passive tree and no gear except for a normal plate vest (no mods) with just a level 4 fireball skill gem in it (no quality). Stats for fireball in the character tab:

Damage per second: 19.45
Casts per second: 1.18
Spell total combined damage: 13 - 19
Spell fire damage: 13 - 19
Spell critical strike chance: 6%
Spell critical strike multiplier: 150%
Chance to ignite: 23%
Number of projectiles to fire: 1

Now, when I add a wand with 10% increased spell damage, I expect the DPS to increase by 10% from 19.45 to 21.395, but the DPS actually only increases to 21.28 (an increase of only about 9.4%).

Obviously, at this level, this is an insignificant amount, but when DPS is in the thousands range, it makes more of a difference (at least in being able to understand how increases or decreases in spell damage changes DPS), and I'm obviously missing something--what's going on here?

Cause your final damage takes crit chance and crit multi into account.

Spell damage doesn't increase crit chance and crit multi.

Shit gets a lot more complicated when we start talking about additive vs multiplicative damage, as well as DoT and stuff like that, but that's a discussion for another day.

"

elitedesolator wrote:

Cause your final damage takes crit chance and crit multi into account.

Spell damage doesn't increase crit chance and crit multi.

Okay, I think I figured it out--I don't believe it had to do with crit chance and crit multiplier--it was GGG rounding down/up (see note below). These formulas are working for me (matching actual DPS in the character tab):

Base DPS Formula (including increased damage percentages):

([{Min. dmg * increased dmg multiplier} + {Max. dmg * increased dmg multiplier}]/2) * ([1/base cast time] * increased cast speed)

***Note: the results of {Min. dmg * increased dmg multiplier} and {Max. dmg * increased dmg multiplier} should be rounded up or down to a full number (e.g. round a result of 14.3 down to 14 and a result of 20.9 up to 21)

+

Critical Chance & Multiplier DPS Formula:

Base DPS * 1 + (base Critical Strike Chance * <1 + increased Critical Strike Chance> * [0.5 + {1.5 * increased Critical Strike Multiplier}])

= Total DPS

Example #1:

Templar with no skills allocated in the passive tree and no gear except for a normal plate vest (no mods) with just a level 4 fireball skill gem in it (no quality). Stats for fireball in the character tab:

Damage per second: 19.45
Casts per second: 1.18
Spell total combined damage: 13 - 19
Spell fire damage: 13 - 19
Spell critical strike chance: 6%
Spell critical strike multiplier: 150%
Chance to ignite: 23%
Number of projectiles to fire: 1

Base DPS Formula:

([{13 * 1} + {19 * 1}]/2) * ([1/0.85] * 1)
([{13} + {19}]/2) * ([1.18] * 1)
([32]/2) * (1.18)
(16) * (1.18)
18.88 = base DPS

+

Critical Chance & Multiplier DPS Formula:

18.88 * 1 + (0.06 * <1 + 0> * [0.5 + {1.5 * 0}])
18.88 * 1 + (0.06 * <1> * [0.5 + {0}])
18.88 * 1 + (0.06 * <1> * [0.5])
18.88 * 1 + (0.06 * <1> * [0.5])
18.88 * 1 + 0.03
18.88 * 1.03
19.4464 = total DPS

Example #2:

Templar with no skills allocated in the passive tree and no gear except for a normal plate vest (no mods) with just a level 4 fireball skill gem in it (no quality)and a wand that gives 10% increased spell damage. Stats for fireball in the character tab:

Damage per second: 21.28
Casts per second: 1.18
Spell total combined damage: 14 - 21
Spell fire damage: 14 - 21
Spell critical strike chance: 6%
Spell critical strike multiplier: 150%
Chance to ignite: 23%
Number of projectiles to fire: 1

Base DPS Formula:

([{13 * 1.1} + {19 * 1.1}]/2) * * ([1/0.85] * 1)
([{14} + {21}]/2) * * ([1.18] * 1)
([35]/2) * (1.18)
(17.5) * (1.18)
20.65 = base DPS

+

Critical Chance & Multiplier DPS Formula:

20.65 * 1 + (0.06 * <1 + 0> * [0.5 + {1.5 * 0}])
20.65 * 1 + (0.06 * <1> * [0.5 + {0}])
20.65 * 1 + (0.06 * <1> * [0.5])
20.65 * 1 + (0.06 * <1> * [0.5])
20.65 * 1 + 0.03
20.65 * 1.03
21.2695 = total DPS

Example #3:

Templar with 43% increased cast speed, 90% increased critical strike chance, 30% increased critical strike multiplier, and 459% increased damage from passive tree and gear with a level 18 flame surge skill gem in it (no quality and no links to support gems). Stats for flame surge from the character tab (no auras, golems, or similar things running):

Damage per second: 9480.7
Casts per second: 2.86
Spell total combined damage: 2393 - 3589
Spell fire damage: 2393 - 3589
Cast speed modifier +43%
Spell critical strike chance: 11.40%
Spell critical strike multiplier: 195%
...Other stats...

Base DPS Formula:

([{428 * 5.59} + {642 * 5.5}]/2) * ([1/0.5] * 1.43)
([{2393} + {3589}]/2) * ([2] * 1.43)
([2,991]/2) * (2.86)
(2,991) * (2.86)
8,554.26 = base DPS

+

Critical Chance & Multiplier DPS Formula:

8,554.26 * 1 + (0.06 * <1 + 0.9> * [0.5 + {1.5 * 0.3}])
8,554.26 * 1 + (0.06 * <1.9> * [0.5 + {0.45}])
8,554.26 * 1 + (0.06 * <1.9> * [0.95])
8,554.26 * 1 + 0.1083
8,554.26 * 1.1083
9,480.686358 = total DPS