Sorcerer Spell Damage Question

[Nivek555]

Hello I just got to level 12 with my Sorcerer and was trying things out to see where I will go from here and I noticed that the damage numbers seemed off. Now I really haven't paid that much attention before, so maybe it has always been this way.

Well first of all I decided to go with Disintegrate for my first level 6 spell and I'll grab flesh to stone next level. For enhancements I have gone fire/ice and I have a Greater Potency VI weapon. The following info is with NO metamagic feats active. Correct me if I am wrong, but Disintegrate at level 12 should be 24d6(which the average damage would be 84) and then the only other thing boosting it should be the Potency weapon for another 40%(which takes it to an average of 118). Now I have tested it maybe 50 times and it seems that the damage always falls in the 165-175 range. So 2 questions here.... First how is the damage so much higher then what it should be? Second, how does something with so many dice never seem to go out of that damage range? You would think that out of so many tries that you would see one that is 30ish more or less then the average. Does DDO have some kind of special way of averaging large dice roll attacks?

When I noticed this I started thinking about my Scorching Ray spell. Each ray is 4d6(or an average of 14) and with +40% from Potency and another 40% from the Fire enhancements, it should be hitting for 25 on each ray, but it hits for 35.

If anyone out there knows what I'm missing in these damage calculations, please let me know and thanks for the help.

[hydra_ex]

Spell damage dice are biased. 1d6 is actually 1d4+2, which is 4.5 on average.

[Nivek555]

Ok good to know that its altered that way, but it still seems like something is missing. If we take Disintegrate again as the example and use the 4.5 average per die, then it should equal 151 average damage after the +40% from greater potency, and like I said I have never seen a hit for less then about 165 and the average is about 170.