Thanks, thejeff!  That sounds like a reasonable explanation.
chrispedersen, I know the area effect is random and can miss units.  What I'm trying to determine is if the targeted square is always hit as part of the blast.  I think it's always hit (as the first blastsqr affected), so I believe a solo unit should always manage to bless itself.
If someone can provide a save game or debug log proving otherwise, I will change my beliefs immediately. 
