You shouldn't be spamming anything in there, Mass Cures nor Mass Heals, unless the lag is bad enough to warrant it. I never said you should.
My TR 17/2 FvS, currently without Mass Heal, is forced to use only Mass Cures at the moment. I only toss one when needed. I do not spam. I watch the bars and heal as SP efficiently as I can.
You know what else I do?
I run out of SP in a pug. In guild runs it isn't an issue. In a pug, my SP is gone. On my capped FvS, who hasn't crafted an SP item yet and as such has a smaller blue bar than the level 19 toon, uses Mass Heal and doesn't have issues with SP.
Telling people that Mass Cures is the way to go is simply bad advice.
Have you even healed a Shroud since the update?