Epic monster's DR useless?

[Kae'Yoss]

If a pc has a +4 weapon (by GMW or GMF) and gets the effect of BA, he could penetrate DR X/+4 or lower and deals extra damage from the BA?

Say you have a +4 weapon and Brilliant Aura for +7.

IMHO, You'd have +4 to Attack, could overcome DR of /+4 or lower and deal +7 Damage with the weapon.

[edit] This may be the reason why the damage bonus the spell grants is so high: it won't stack with the enhancement bonus to damage a magical weapon gets, so it should be higher than normal or that part of the spell is useless with magical weapons.