Yeah, this is one thing they should definitely clarify. The global post you get to from the launcher says "Heroic/Epic XP boost" and the box says "Heroic experience".It's heroic/epic XP boost; they don't effect boxes. You need a vip xp boost event to do that.
Yet another time when one can understandably misunderstand. It says heroic experience on both, and the stone says it can be boosted by other effects. Kind of unnecessary cause for buyers regret once again.
On a separate note, I'm thankful for this weekend bonus. I really enjoy when people show up in droves to play content together, that's when DDO feels at its best. I've been having a blast outside prime time US lagginess (on Khyber). On that note, I think xp buddy boost should be up in some form by default to encourage such consistent partying from players, even if it's not quite as lucrative as the combination of +25% xp and treasure hunter bonus.