When melee units attack a structure, I understand that they are limited to 250 damage. Are they supposed to use all of their bp to do this?

I have melee units that can do from 880-1408 damage (with 100% bp after moving next to the target) that are going to zero once they do their 250 damage to a palisade. My thought is that they should be dropping down to about 75% bp at most, not 0%. I think this must be a bug.
Anybody have any insights that I am missing?

H.

Yes, otherwise you could just attack with them again for another 250.

OK...thanks.

One more huge advantage to the defense. I will have to make small wall attack units in the future and save up big breakthrough units to follow.
Cheers,
H.