Loss of control damage

Inner sanctuary with Solace of the Peaks - does damage over 8 secs and inflicts 40% chill.
Testing additional loss of control damage.
Swapped LVL 5 Battleguard - which has no damage passives with LVL 10 Pain of subjugation which "deals 16% increased damage to enemies suffering loss of control" - both at 150 reso
Damage ticks with battleguard - 2642, 2958, 3032
Damage ticks with Pain of Subjugation - 3065, 3431, 3516 (16% increase compared to above)
This brings us to the question - what exactly does chill do? seems to increase damage over the duration of the dot.