Value of all-out assault? (bodyguard)

[Grinning]

All-Out Assault: At 5th level, the Bodyguard can concentrate for a round and focus his strength, making all of his melee attacks for the next three rounds inflict maximum damage. However, at the end of each of these three rounds, the Bodyguard takes 10 points of damage from the incredible strain. This ability can be usable three times per day.

I've seen that typically builds with bodyguard (or neverwinter nine) tend to stop at 3 for obvious reasons, but does anyone have experience with using all-out assault? On paper it seems pretty good, provided you can afford to take 30 damage over 3 rounds, or 90 damage a day if you use up your 3 uses. The class itself has good saves, high bab, d8 and skills; it opens up heal which would counteract the damage taken from all-out assault itself.

Is there some mathematical reason why all-out assault isn't worth it?

Thanks.

[matelener]

Concentrating for a round makes you lose more damage than you gain. The maximized effect works only with the weapon damage roll, so it's not a lot of damage. With a longsword, you'd gain just 3.5 damage. (1d8 dmg becomes static 8)