Ok I’ve read OPs post and went through my abilities to try and make sense of it all.

Here is how I understand things:
There are attacks classified as Melee/Range which trigger shields and their absorption as stated in the shield chance tool tip.
There are attacks classified as Force/Tech which do not trigger shields.

Each of these attacks has a specific damage type:
Kinetic/Energy which is mitigated by armor.
Internal/Elemental not mitigated by armor.

I went though my Powertech shield tech abilities and as best as I can tell. Most abilities ARE mitigated by something and those that aren’t have a lower base damage than other abilities. Here are 3 examples based on numbers from my own toon:

Rocket Punch (Tech): Engages the jetpack, allowing you to strike the target with a heavy punch that deals 1222-1263 kinetic damage. This attack not trigger shield but it’s damage would be mitigated by armor.
Unload (Ranged): Unloads your blaster into the target, dealing 577 – 703 weapon damage every second for 3 seconds which is up to 2,109 energy damage. Weak and standard enemies caught in the blaster fire are stunned for the duration. Fires both blasters if dual wielding. With this attack it has both a chance to trigger shields AND is mitigated by armor.
Flame Burst (Tech): Fires a burst of flame at the target that deals 681 – 749 elemental damage. This ability is not mitigated by shields OR armor.

Now here are my damage reduction and absorption stats Damage Reduction 50.97%, Shield Chance 40.99%, Absorption Rating 36.68%. Applying appropriate mitigation of someone like myself to the above abilities assuming max damage value:

Rocket Punch 1263-50.97% = 619 damage
Unload (2,109-50.97%)-18% = 848 damage assuming I absorb only 50% of time like OP does which case my real chance is even less. Also since this ability is channeled it is unlikely all 3 ticks will hit for max damage.
Flame Burst 749-9% = 681.59

Final Thoughts
Now I obviously haven’t parsed through every skill in the game but which I saw from my own abilities was that my Tech attacks that do Elemental damage did a lower base damage as if they already built the mitigation into the ability itself. For example my Flame burst ability automatically does 41% less damage based on tool tips than my rocket punch does. Obviously all these numbers will change based on how you spec but ultimately I think it all evens out. Can someone else go through their own different class and see if this seems to be the case?