[number] At the end of each other's [number] , time to activate / invalidate the effect and [number] to check the special state .
So, essentially, they had to flip a coin on their turn; if heads, they'd cure Sleep; if tails, they wouldn't. This is definitely still more unbalanced than the Sleep status now, as it allows you to possibly cure Sleep between turns.
Source: my best interpretation of This Page.
Hope I Helped!