Can someone explain why Hypothermia shows more dmg thank Awaken Cold Pen for Omni TS

Hypothermia gives 29% more dmg

Awaken cold pen gives 39% more cold pen. If we're omni, my understanding it's just a straight up 39% more dmg since we always penetrate enemy res to negatives. Plus it gives you cold exposure.

Yet, POE Ninja shows Hypothermia has higher dmg. Everyone seem to use hypothermia, don't see anyone using cold pen. (with crit dmg, ele atk, viscous proj)

Is my understanding of res penetration wrong? Isn't any penetration past negative is just linear %more dmg?

Plug them into PoB and see. In most cases hypothermia will have slightly higher dps than Awaken Coldpen. It's just the way the math works. If you go into Calcs tab on PoB and select TS. You can see the break down of the formula. If you hover MH Total More and MH Eff Dps mod you can see the difference between the two. Hypothermia gets apply before being multiply at the end with penetration multiplier (this is a ratio), hence it gives bigger hit damage. In order for cold penetration to be really worth it you'd need like 2500 omn.