While testing different builds for DEVESTATION DRACTHYR some of us have realized that if you spec scalecommander with terror of the skies, your deep breath stun goes from 3 seconds, down to 1 second.
If you swap from scalecommander to flameshaper, it goes back to a 3 second stun. Then back to scalecommander and its a 1 second stun again.
Somebody posted its also applying 2 stun DRs for every deep breath with scalecommander as well.
I tested in PVP and PVE and found the same results in both.