Damage multipliers seem to affect your friendly npcs and summons.
Can you please post your save game, and also an update request?
Please use the update notification system to report a game patch, update or to report that the trainer may not be working with the latest version of the game. If 3 or more reports have been filed, consider BOOSTING the priority of this title for a faster turnaround on the updated trainer.
Damage multipliers seem to affect your friendly npcs and summons.
This cannot be fixed.
In oblivion exp is based off armor degradation for the respective skills, how does this trainer work with it?
EXP multiplier affects the whole exp system in the game if that's what you mean.