Path of Exile Damage over Time change example

Assume the following:

lvl20 Fireball
  739-1109 damage
  924 avg.

100% increased spell damage
50%  increased burning damage
100% increased fire damage

0% resist, no support gems (to keep it simple)

OLD SYSTEM (2.6):

Fireball hit damage multiplier:
      1	base
 + 100% spell damage
 + 100% fire damage
----------------------
 = 3.0

Fireball hits for 924 * 3.0 = 2772 damage.

Ignite damage multipler:
      1	base
 +  50% burning damage
 + 100% fire damage
-----------------------
 = 2.5

Base ignite damage/second is 2772 * 0.2 = 554.4
Final ignite damage/second is 554.4 * 2.5 = 1386

NEW SYSTEM (3.0)

Fireball hit damage multiplier:
      1	base
 + 100% spell damage
 + 100% fire damage
----------------------
 = 3.0

Fireball hits for 924 * 3.0 = 2772 damage.
This hasn't changed.

Ignite damage multipler:
      1	base
 +  50% burning damage
 + 100% fire damage
-----------------------
 = 2.5

This also hasn't changed.

HERE IS THE CHANGE:
Base ignite damage/second is 924 * 0.4 = 369.6
                              ^     ^
                              |     |
 This is Fireball's BASE damage,   This is ignite's base damage, which has been buffed
 not the hit's damage.             from 20% to 40% per second to compensate somewhat.

Final ignite damage/second is 369.6 * 2.5 = 924.