Using list hieararchies, Anaplan will aggregate to all levels of the hierarchy and you can add time as a dimension to modules to see the accumulation by time in addition to the hierarchy level. Think of it as a rubiks cube. All you have to do is make sure you have applied the Summary settings on each of your line items to get these aggregations and also make sure you are using lists that are parented to each other.
Anaplan is totally flexible on how you set it up to do planning. There are good ways and bad ways of constructing models though. I would highly encourage you to spend some time taking some of the trainings available as well as reading the Planual for best practices within Anaplan construction. If you are new, they all may not make sense at first, but as you start building, the concepts will become clear for you. As for differences, I am not an SAP expert, but I do know that you can configure Anaplan to perform your planning process in whatever order you need, part of what makes it so great!