If Multi-Step is configured in Case Designer, if we open the flow for it, it will be using Screenflow, It seems like we can use either of them, one we need to create manually and the other will be created automatically.
Also i have observed that in multi step form i don't see any difference by checking "Perform post processing when navigating away from step" check box. In both the cases (enabling and disabling the check box) the post processing DT is running.
My understanding is when i enable the check box then as soon as i complete the particular screen post processing DT should trigger. If i disable the check box then once we submit the multi step form that time all post processing action should run.
Currently its not the case irrespective of the checkbox selection all post processing actions are running on submission of that particular screen.
I think "Perform post processing when navigating away from step" will be useful only when navigating back from the step, if we are continuing the steps, then flow action will be submitted and post processing actions will be performed.
Going forward and otherwise naturally submitting the flow action will fire any/all of your post processing configuration.
My understanding of this checkbox is to also allow it trigger/fire if a user also happens to navigate away from this stage/step.