Brimstone blast (Complete Arcane p.132) is intended to be a non-stacking damage effect as opposed to vitriolic blast which just adds more damage every round. However, the wording used to accomplish this is as follows:

A creature burning in this way never takes more than 2d6 points of fire damage in a round, even if it has been hit by more than one brimstone blast.

Does this language prevent brimstone blast's bonus damage from benefiting from bonus damage such as critical hits or mortalbane (Book of Vile Darkness p.49)?

Brimstone blast (Complete Arcane p.132) is intended to be a non-stacking damage effect as opposed to vitriolic blast which just adds more damage every round. However, the wording used to accomplish this is as follows:

A creature burning in this way never takes more than 2d6 points of fire damage in a round, even if it has been hit by more than one brimstone blast.

Does this language prevent brimstone blast's bonus damage from benefiting from the bonus damage from Mortalbane (Book of Vile Darkness p.49)?