Interesting how this stuff either changes over time, or is handled differently by different agents. I've never 'given back' segments, but others here have commented fairly recently about getting money back from extra segments deleted from the trip, quite different from
'WHEN THE REROUTING RESULTS IN A REDUCTION TO THE NUMBER OF CONTINENTS OR XTRA FLIGHT SEGMENTS PREVIOUSLY CHARGED, NO REFUND WILL APPLY."

Is that a new-ish rule?