I am able to answer instead of ArmorVil, since we speak to each other almost every day. Well, Dual and Dual Drain are always enabled together. In AVgr (in the final release), almost every attack that involve the "Poison" status will have "Dual/Seizure" attached to it, but the reverse is not always true. I found some issues, tough, since the Dual/Seizure status is meant to be used "as-is" and so used with others... well... In Total Grudge, this is different *checks kernel and scene of total grudge* There is a magic that inflicts Seizure without Poison. I don't want to spoil much and ArmorVil don't want to create a thread for that until the final release...
EDIT : It was workarounds (accepting the limitations...)