I pretty much do the same that you are, with this difference...
Judge Seal Of Wisdom and keep it on myself. Get as many mobs with that as you can and just tab through them to refresh.
I keep BoS on me for the return damage, and ret aura for same reason.
Rarely will I pop holy shield, and conceration is after I see my mana build back up to where I want it too.
Downside? It takes longer to kill them all. But we pallys were not build for dps. As I've been quoted, "I can't kill a rat, but he could beat on me for a whole year and I'd never die".
The downtime inbetween for me is usually a bandage and I'm off. Though I've heard of the downgrade in Conceration, I've never tried it. I think that if you judge your mobs with Seal of Wisdom and wait for you mana to refresh, the time difference between that and using a lower rank conceration won't be that big. The biggest difference you'll see is if you judge wisdom on your targets and they start giving you that mana back.
*Note one rank down for you is 85 less mana and 52 damage(6.5 dps).