I fear you are incorrect. If what you say was the case, then AS damane that the sul'dam tried to use as weapons would have died from the conflict. We know this is not the case. The AS are unharmed, but they simply cannot be used for that purpose. The a'dam works primarily through pain and torture breaking the victim. The oath rod however somehow implants the command directly to the mind through somekind of super-compulsion, making it far stronger.

The oath rods is more powerfull than the a'dam basically. It cannot be broken by the sul'dam. Even after the damane has been utterly broken by the torture, the oaths still stand.



I think a better oath would be to make an oath about not channeling at all while collared. Or perhaps an oath not to aid the Seanchan in any way, period. That way it would not matter if the Seanchan broke you, the oaths would still stand and the moment the AS tried to do anything, whether channel or reveal some secret information, the oaths would kick in and stop her.

This would ofcourse mean that the Seanchan would quickly abandon all efforts to capture AS, and just start killing them outright. But it would mean that any weaves discovered by the AS would remain secret, and that the Seanchan could not replenish their damane numbers with AS prisoners.