How to actually calculate scalings on abilities?
Let's take Caitlyn's ult for example.
http://puu.sh/dG8ix/bf0910c493.png
I'm assuming that at first rank, it deals 250 damage flat. With full ranks, it should deal at least 700 damage. So, how do I go about actually calculating that +200% bonus AD? Is your base AD calculated into the % scaling? What if you have the +80 AD from Bloodthirster? Or say, a +4 damage from runes? What is percent-scaling, really?
Please explain so that it can be applied to all abilities, since not everyone is interested in Cait's ult. X)
Thank you! 