I was just looking at someone's question about defend tokens when a question pooed into my head:

If you counterattack using your units defend token and you both roll the die at the same time, what happens if you both roll flags?

Obviously the defending unit would ignore the first flag due to stalwart, but what if you both rolled more than one flag each? Do you both retreat or do you just work out the difference (like you do for morale if both units were eliminated)?

Monk

My personal opinion is that you both retreat as much as you are forced to retreat. Sort of an anti-thematic bounce effect potentially, but I can't see the rationale for taking the difference either, as retreats are not shared like morale.