How do I get OS X 10.11.6 to return my free space?
Rebuilt the spotlight, then rebooted and reran disk utility. 
It showed a problem with the free space index. 
Rebooted into recovery, ran the disk util, and it repaired the disk. Unfortunately, df -h (the lower free space amount) seems to have been correct all along, and disk utility and selecting info for the drive from finder were incorrect. 
All are in sync now.