It’s true that Chinese government statistics are unreliable, but unlike the Soviets, they tend to be underestimating rather than overestimating. The main reason for this is that China wants the world to think it’s a developing country (to get aid and also less flak for things like global warming and pegged currency exchange rate). This World Bank revision just gives the Chinese an excuse NOT to appreciate their currency.
I'd be shocked if that were the case.