Do Cleric life magic and Bard song stack?

[Spiteful]

Unlike most enhancements, you dont have to choose between the two when you multiclass, so I was wondering if this is because one also improves sonic, and the other positive energy spells, or whether the 10% improvement to healing spells stacks.

[Lithic]

I wouldn't be surprised if cleric enhancements only affected the cleric version you cast, while the bard one only affects the bard version. Sort of like a 10 wizard/1sorc casting shield will either cast it for 10mins, or 1 min, depending on which side of their personality cast it.

[Greydeath]

By themselves, the Cleric enhancements affect the Bard spells & the Bard enhancements affect the Cleric spells, I suspect that they would indeed stack in some fashion.