From a personnal experiment, don’t believe the greedy people selling power-leveling services twice or even 50% higher than the normal price : hypers DON’T stack with x2 events.
Some will try to make you believe it’s “not really x2, but you get like x1,5 the normal exp”, and that’s scam too. Why the hell would you get 1,5 more exp if hypers don’t stack ?
I recorded the exp I get at the same level before and during x2 event, and there is no difference.
PWinsider saves your wallet 😉