The Seanchan in general have fairly little experience fighting people who use the OP against them, barring the occasional rebelling High Lord or Lady who had damane and sul'dam. Things must have been different centuries ago - while the Empire was expanding and conquering "AS" kingdoms, but by the time the Alivia was born, the Empire was already pretty much consolidated. Damane vs. Damane battles still happen, but far more rarely as most damane are owned by the Crystal Throne. Lords who are allowed to own damane don't have a lot of them.

“I read there were four hundred damane on each side at Semalaren, and that was a slaughterhouse. Half the Imperial army on the field dead and better than three out of four among the rebels.”

The Conquest, however, also called the Consolidation, required nearly three hundred years, and another two centuries passed before the last resistance was expunged and Luthair’s descendants reigned a land totally at peace. So far as any empire can be at peace.

He had missed the last battles of the Consolidation by two hundred years, but some of those rebellions had not been small. Two years fighting on Marendalar, thirty thousand dead, and fifty times that shipped back to the mainland as property.