Is the last "row/child" always the one you need to add numbers into?

Hi!

I’m looking to add task-trees under within a very simple sales budget - in other words, under a budgetpost I would like to add the projects and then the tasks that are needed to complete that budget goal. Doing a very action oriented sales budget kind of. But I run into a problem when the last " row/child" I use always becomes the one that you need to enter the numbers into.

Ideally, I world like the third row to be the last row where I enter numbers and underneath that I would build task-trees that I could then copy/paste to my own and colleges OmniFocus. Is there a way to customize that today?

All the best!