In my current ACW game (latest patch), I've taken some MAJOR losses in NM from a series of naval battles that weren't particularly heavy in losses being lopsided or ships being sunk. On average, though, I lose 5-6 NM any time there's a big ironclad engagement. I just don't get the severity of the NM losses though, considering that during these engagements, I've only lost a handful of ironclads, and in several of them, there's been no losses whatsoever as far as destroyed elements.
Just seems excessive, I think there's been about 20-25 NM shift from these battles, so it's pretty signficant... far more than the actual strategic damage done. Maybe would make more sense for the NM losses to either be applied only to destroyed elements, or a reduced percentage for damage-only?