I get the point that a new bouncing bolt is weaker on a target that has been hit before.
If you only hit one target and the "chain" is bouncing again, than it is not considered a "chain" anymore, than it would be more of a "lightning strike", because obviously a chain needs to bounce off at least between two targets to consider it a chain.
The DPS efficiency on more targets follows currently an order like this: 100%-200%-300%-400%-500%-600%[-700%-...it is not really proven how many target can be hit, we leave this topic for later stages, when we found out how this works]
This means the increase is linearly. Damage-Efficiency-Bonus: per enemy 100%.
Your buff example would look like this:
1 Target__2 Targets__3 Targets__4 Targets__5 Targets__6 Targets
__19.9______ 35_______45________50_______55________60
__100%____177.78%__228.57%___253.97%__279.37%___304.76%
___/______+77,78%__+28,57%___+11,11%____+10%____+9.09% (Damage-Efficiency-Bonus)
Since this is a mix of a linear increase function add up with a decreasing exponential function. Here the efficiency drop is really strange because of the hole function.
So I thought changing the damage reduction from dividing by 2 was the mistake, so tried it with dividing by 6 -results:
1 Target__2 Targets__3 Targets__4 Targets__5 Targets__6 Targets
11.9987___23.8888___35,0001___43.3334___51.6667_____60
__100%____199.09%___291,7%___361,15%___430,6%____500.05%
___/______+99.09%__+46.51%___+23.8%____+19.23%___+16.13% (Damage-Efficiency-Bonus)
Like this, the change of the efficiency decrease rate would look more healthy (Bonus is almost halving itself for an amout of targets between 2-4, but still with the 5th target it just gets weird as before), but this would be more compareable to the Damage-Efficiency-Bonus-levels which are on live-servers.
What happens generally? The more Mantis you fight against, the more damage you need to tank. So with each Mantis the damage to tank increases by +100%, making it 100%-200%-300%-400%-500%-600%, the same we could say with pvp without looking specificly at the shipclasses. So the risk in facing several enemies in PVE is a big factor which makes it logical that that the risk you have and the damage output your LC provides, are in a harmony in a scale of 1:1.
Else for each enemy the DamageOutput-DamageInput-risk-ratio will shift like this with your numbers
1 Targets = 2:1
2 Targets = 1,75:1
3 Targets = 1,5:1
4 Targets = 1,25:1
5 Targets = 1,1:1
6 Targets = 1:1
These risk ratios prove that the more enemies your are facing the less it is worth to deal more damage while taking also more damage at the same time. The concept of the lightning chain will switch from trying to to fight at least 4-5 enemies to only fight against 1-3 enemies maximumly because the benefit of more damge is not worth risking. The lightning chain is the first ship component in the game to be a double-edged sword (I know there is the ifrit cortex aswell, but it isn't a ship component xD)
The risk ratios of my try inspired by your idea would look more viable like this:
1 Targets = 1,2:1 (my opinion: it makes no sense to bounce off the the same target to hit it again and again)
2 Targets = 1,195:1
3 Targets = 1,167:1
4 Targets = 1,083:1
5 Targets = 1,033:1
6 Targets = 1:1
The DamageOutput-DamageInput-risk-ratio will buff like this slightly and be more consistent in different scenarios against mulitple targets. So the risk ratio will still be "riskier" to fight against more enemies, but the benefits are in comparisons to the risk ratios above more worth taking.
