Lightning Strike of Arcina Skill question

Hi

I have a question.

Use Skill : Lightning Strike of Arcina

Medium Cluster Jewel : 10% increased Projectile Damage
Follow-Through : Projectiles deal 15% increased Damage with Hits and Ailments for each remaining Chain

Q : Is it correct that Lightning Strike of Arcina skill is 15% x 8 with 9 chain as of 20/20 and if you use Follow-Through with 8 without the first chain, you get 120% deal?

p.s : If I use 3 Follow-Through, will it be applied ?