Simple vs Advanced Portfolio Modeling?

I've read through the manual about these two features, but it's not clear to me how, or if, they work together. The return on specific assets is bound to reflect the return of the account(s) in which the asset is held. So if one chooses, say, a 3% return at the account level, and a 7% return on assets held in that account, which one determines the tool's calculations? Does advanced overrule simple? There's no toggle or button to indicate which will be used, so I'm guessing that somehow these numbers work with each other?