[thejeff]

The 5 AoE 1's combine.
Maybe that's the problem. A large AoE spell hits a number of areas around where it is targeted. Which particular areas are determined randomly, so even with precision 100, with only one target, the actual may not be one of the areas randomly chosen.

If I've got that right, an AoE 1 bless should always hit a single sacred target, just like the caster only version would.