Target Rate weighted, too?

Does it work like enemy action patterns?

So with 4 actors, each one has a 1/(1+1+1+1) chance? And when one of them has 500% rating, it becomes 5/(5+1+1+1)? And when another one has 300% rating, his actual chance of being targeted becomes 3/(5+3+1+1)? Is that how it works?