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SCH is suited as the DPS-Healer like WAR is the DPS-Tank, and they have so many skills that support them in this design space, rouse, bane, DoTs, shadowflare, 3 single target attacks, and energy drain, most of which compliment them as a healer, as they deal damage while the faily or player heals. That is how the job is designed whether you like it or not, and content is designed to allow them to be played that way.
Edit: I should add to the above is that if both Healers are 100% healing, then you WILL be overhealing and wasting time and MP, the exception being lots of deaths or a healing check.