User blog comment:InTheCage/Sphere question/@comment-25251916-20150219053236

Damage Formula: ATK * (1 + Sphere + LS1 + LS2 + P + O + aBB + DM) * C * EW * Sparks

Under the section of spheres, angelic foils would provide a 75% attack boost which translates to .75 additive bonus. The reason the damage increase is higher on spheres like Batootha is because of not only the attack boost but it's effect to increased spark damage. As shown above, spark is shown as multiplative value along with crit and elemental weakness.

I'm not sure how you would get an increase in damage from drevas or legwand as their attack values are relatively lower than angelic/batootha. There is more info regarding the other type of spheres but I'll link an analysis of how damage is calculated since it has been known for a while.

http://appinvasion.com/threads/guide-an-insight-into-damage-calculations-crit-update-3.21408/