You chose that character to harp on. We could just as easily use my other battle cleric that has a triple positive greataxe with superior devotion VII on it.
But I want those people reading this thread to understand that quicken ISN'T invaluable. In fact, I play without it every day, and I can't remember the last time I didn't complete a quest (actually I do... it was last night in Threnal but it was because of a UI bug and not healing).
The reason people now think it's invaluable is because of a handful of posts like this that claimed it so, and that belief caught on like wildfire among people that were either new or incapable of critical thinking. The end result of that senseless garbage is a bunch of new clerics talking about how they can't afford to play a cleric because they waste all their mana on quicken during simple quests. My goal is to rid this game of such thinking.
I forgot throughout the last two pages that I also have Lorrik's necklace, so I'll mention it now (effectively have the same as full enhancement line).
I'll be honest with you... I don't know where the hell you're getting all these numbers. Here's how I see it and you can correct me where I'm wrong:
Mass cure serious wounds with empower healing [(3d8+15)*190%]/46 = 1.18 healing per mana.
Mass cure serious wounds with maximized healing ([(3d8*200%)+15]*140%)/65 = .9 healing per mana.
Now this time with a greater devotion VIII item to appease the masses:
Mass cure serious wounds with empower healing [(3d8+15)*240%]/46 = 1.49 healing per mana.
Mass cure serious wounds with maximized healing ([(3d8*200%)+15]*190%)/65 = 1.23 healing per mana.
Now I know the maximized number probably isn't exact because I don't know the formula to only apply 200% to the variable average and still keep the linear percentile, but if it isn't accurate then the error is in favor of maximize. These numbers still show that in all instances (albeit without quicken) the empower heal feat is more efficient.
EDIT: Read second grade math for dummies... fixed math.