Sometimes, it may be helpful having the net total for selected movements. It may be seen as a nonsense but when I am trying to match the different transactions in a card with the actual payment I need to do it manually (the idea is just show in the bottom of the screen the net total as I select transactions, not a big stuff for you guys :P)
Point taken, we are considering something similar. It is not that easy as it may sound though, I cannot tell when this might be ready. You can do this with the Advanced Reconcile on Mac (only) though.