Every single strike is - or has been - scored as 'slightly below average'?
That is supposed to be a serious spell, capable of doing some real damage to "ruffians".
The three missiles do a total of 6 - 15 points of damage for an average of 10.5 points damage. You did a total of 10 points of damage with your three missiles (.5 points less than average).
Don't feel too bad. Syllin has done a total of 40 points of damage, Portia has done 6 points of damage and the Count has done 6 points of damage. The ruffian have also missed and hit themselves for a couple.
As far as everything below average, it's just the luck of the dice and @ravenvii's rolls. Maybe if we all change our names to Portia, he will roll better for us