@Riot Regarding Fiddle

Why do interrupts while channeling his ult put it on the full cooldown? Champs with channeled ults that have instant benefit (i.e. Malzahar, Galio, etc.) make sense to have a full cd on their ulr if cancelled. However. champs with channeled ults without instant benefit (i.e. Cait) do not have this downside and have their ults placed only on a short cd. So why does Fiddlesticks, who only effectively stuns himself for the duration of the channel, get the negative side effects of an instant benefit channel?