Undersstanding Ad Sharing

I am still not quite in tune with the ad sharing plugin. Questions and comments do follow.

(1) Ratio - Seems a numeric input box allowing the admin to refine the split a bit would add flexibility. My opinion is that reading data from an input box is also a bit easier than configuring a drop down box. Not a biggie, but wish you would think of it. I have a personal affinity for giving 40% commission to affiliates and 10% to JV partners, so that number sticks in my mind.

(2) About how the sharing works. Is the blogger allowed to insert their own complete advert that shows alternately with the admins ad? Is that how it works? Sort of like an a/b split?

(3) How about if I wanted to allow the blogger to merely edit my code (i.e. insert an affiliate code into the advert link code)? Meaning, the same ad shows all the time, but I can then actually use affiliate software to track and pay these folks.

So, is my understanding (meaning it's like an a/b split) correct? Would you think of the comments as an add on feature?