Well, first thank you FFG for making Fire Flask more useless !!
On the other hand since the rule on attacking multiple monsters (p.10) seems to cover only "attack" actions I suppose other action like Radiant Light (Disciple) and Tempest (Spiritspeaker) are not affected.
At the same time skill like Advance are also not influenced by this rule since they are not targeting multiple monsters but they are a bonus attack.
Is there some additional considerations about this rule I am missing ?? Yesterday we have forgot to round up the damage (and we round it down... ).