Elemental Invocation - A More Efficient Trigger Skill than Cast on Shock?

Currently playing an archmage Cast on Shock [CoS] build (real original, I know) and pathed over to the "Invocated Efficiency" node on the top right side of the tree (Recover 3% of Mana when you Invoke a Spell, Triggered Spells deal 45% increased Spell Damage). The wording on the first part of this notable seems to be specific to invocation skills vs. the broader trigger class, and the in-game detail text of the keyword "Invoke" would seem to back this up - "Invoked Skills are those Triggered by Invocation Skills". To me, this read as though if you path to this node for a Cast on X build, you would get the damage, but not the mana recovery. Running with archmage, that 3% recovered is relatively substantial, and would represent an overall 60% reduction in mana usage from archmage.

This background led to me taking a look at the mechanics of Elemental Invocation [EI] as a potential trigger as opposed to CoS. Immediately what stuck out to me about EI was the base 3 energy per shock generated vs 2 for CoS, granting what is essentially a 50% more multiplier to energy generated right off the bat. This seemed like a huge win and I was curious why more builds weren't running this as a trigger mechanism. When looking for reasons to / to not swap over to EI, I thought of the following:

1. It does require dexterity, it's a min level 8 gem which requires 34 dexterity. Dex really isn't a skill that is needed at all on an archmage build beyond a couple gem sockets, so this did require a 4 point respec from int -> dex.
2. Since scaling the EI gem level requires increasing levels of dexterity, typically most people would I assume keep the gem level at 8, which translates to only a 21% increased energy gain buff from the gem. This would be used in place of a CoS gem, which at level 19 + 20% quality will grant 69% increased energy gained -- a difference of 48% increased energy gained (not using gem lvl 20 due to current rarity). Even with no increased energy generation elsewhere on the tree EI comes out on top, but as all sources of increased energy generation are additive, EI quickly takes off and ends up generating more energy on average per shock with more investment in it, with ~23% more energy generated overall at 100% increased energy generated. Scaling dex slightly higher also gives access to a level 7 Voltaic Mark, which grants 50% more chance to shock + 30% increased effect of shock. This dex requirement could potentially be further lowered via vaaling one down to level 6 (not confirmed if this is possible).
3. The trigger activation mechanism for EI has been seen as clunky to use, with no way to automatically cast on reaching the cast threshold. Regarding this, I found that the classic 'numlock' trick from POE1 appears to continue to work in this game, which results in EI being automatically cast immediately upon reaching sufficient energy to trigger the socketed skill.

Here is a table outlining energy generation in more depth:

Inc Energy Gain (outside of gem)	Total Inc Energy (EI)	Total Inc Energy (CoS)	Resulting Energy (EI)	Resulting Energy (CoS)	Unique hits to trigger EI	Unique hits to trigger CoS
0%	21%	69%	3.63	3.38	4.13	4.44
10%	31%	79%	3.93	3.58	3.82	4.19
20%	41%	89%	4.23	3.78	3.55	3.97
30%	51%	99%	4.53	3.98	3.31	3.77
40%	61%	109%	4.83	4.18	3.11	3.59
50%	71%	119%	5.13	4.38	2.92	3.42
60%	81%	129%	5.43	4.58	2.76	3.28
70%	91%	139%	5.73	4.78	2.62	3.14
80%	101%	149%	6.03	4.98	2.49	3.01
90%	111%	159%	6.33	5.18	2.37	2.90
100%	121%	169%	6.63	5.38	2.26	2.79
110%	131%	179%	6.93	5.58	2.16	2.69
120%	141%	189%	7.23	5.78	2.07	2.60
130%	151%	199%	7.53	5.98	1.99	2.51
140%	161%	209%	7.83	6.18	1.92	2.43
150%	171%	219%	8.13	6.38	1.85	2.35

What this means is that we can hit breakpoints with EI with overall lower investment, or otherwise hit breakpoints that would otherwise be infeasible for CoS.

So anyhow, am curious to get feedback on this, are there things not accounted for, is my usage of a janky numlock trick for activation not a viable longterm strategy (lol)?

One final thing, after testing EI, I'm pretty sure the thing that started all of this -- the mana recovery from the Innovated Efficiency notable -- is bugged, I didnt see any noticeable difference in mana generation.