I haven't healed since my MC days but my guild has started raiding and or Disc Priest seems to go oom really fast. I noticed she was using Flash heals and never using Heal. She said that's the right way to do it. So That's Why I'm here to double check facts. Also trust me it was not the priest fault for no boss was downed.
this is the data from tonights failed boss fight
Power Word: Shield 17.2 %
Divine Aegis 14.8 %
Prayer of Mending 13.9 %
Flash Heal 11.7 %
Penance 8.1 %
Renew 8.1 %
Spirit Shell 7.7 %
Greater Heal 6.4 %
Glyph of Power Word: Shield 4.7 %
Prayer of Healing 3.4 %
Power Word: Shield 2.7 %
Angelic Bulwark 1.1 %
Healthstone 0.1 %
Atonement 0.1 %