It may be that a monk has committed two offenses entailing suspension, both concealed for two months. He’s sure of one month, but unsure of the other. He asks the Sangha for one month probation for the month he’s sure of, which he gets. While on probation, he becomes sure of the other month. He considers all this and thinks, ‘Let me ask the Sangha for probation for an additional month for those two offenses.’ He asks and gets it. Counting the previous month, that monk must stay on probation for two months.