Incredible that this basic idea was suggested in October 2009 and has been "Under Review" since August 2013. Still not implemented. We are actively searching for another e-commerce provider because it's just too long to wait for something that should have been possible from the beginning.
Absolutely need this!
Yes! Sometimes people order multiples of the same item by mistake. We have to issue a partial refund via our payment gateway, but then the numbers don't match up with 1SC. It creates an accounting headache almost every day. We need to be able to adjust orders or have the ability to issue partial refunds from within 1SC (already voted on this too).