"chain" support gem poorly explained

hello,

i have many questions about the "chain" support gem, because its description is a bit confusing.

1. it says "chain +1 times" AND "chain 100% more times".

is this just saying the same thing twice, because most skills only chain once to begin with; meaning this gem just makes the skill chain twice?

or does it add 1 more chain and THEN chain 100% more times; meaning 1 + 1 = 2, then 100% more = 4 times in total? thus a skill that chains twice to begin with (maybe due to equipment adding a chain) will end up chaining 6 times.

or does it mean something completely different?

2. it says "50% less damage with hits".

in the case of "lightning arrow", does this "50% less damage" apply to the original projectile, or the chaining "beams", or both?

i hope you can see how confusing this all sounds. my thought all this time was that it adds "1 OR 100%" to chains, which usually only adds to 2 chains, which means total damage output is actually the same, or even lowered when you're only fighting a single target.

please help me understand this support gem better.

thanks.
-az

Most skills chain 0 times.
"chain +1 times" : 0->1
"chain 100% more times" : 1->2
Now it chains 2 times, i.e. hits 3 targets.
"50% less damage with hits" : 3*0.5=1.5
Overall skill deals 50% more damage, but it's spread across several targets.

If your skill initially chains once (i.e. hits 2 targets), it will chain (1+1)*2 = 4 times, hitting 5 targets.
DPS changes from 2*1=200% to 5*0.5=250%.

"50% less damage" applies to any hit, the source of which is supported skill.

It adds 1 chain to the skill (some skills can't be chained, like the ones that pierce all targets or explode) and then increases it by 100%.
As the guy said, but speaking better now, it doesn't increase your damage at all, especially since the chain needs some source to chain, and bosses are mostly 1v1. I know there are some skills that you can use to chain, but they have bad DPS and limit to chain, so if you use this support on an already chained skill, like storm orb (don't know the name correctly), it will destroy the chained skills in literally 1 second and the damage will be halved.
Maybe there is some skill that has a lot of damage, but is mostly single target, so using this support gem will improve to clear the small monsters.

Overall, this support gem has little use and the 50% less (it's LESS and not REDUCED, be careful with the LESS guys) is just insane.