Assign variable tag

[Illyahr]

I wish things had stuck with Value fields instead of Value tags. They're easier to alter.

So I want to provide a value to xFastHeal based on variables. It will be

perform hero.assign[User.Ability]
var bonus as number
bonus = adjust
(Ability count * 20) + (Ability count * adjustment)
perform hero.childfound[xFastHeal].assign[Value.bonus]

It doesn't recognize "bonus" so how do I assign this?