Not necessarily. With respect to OAS, it has to do mainly with the fact that, if the fraud isn't identified at a given point, the person could continue to receive payments for another 10, 15, or 20 years. Therefore, the overpayments could really add up. If the fraud was detected in time and at the right time, the overpayment would be minimal. If, however, payments continued to be made, the overpayment would be considerably more.
The prediction model assumes that people could continue to receive payments for a period of approximately seven years, so that's how the amount is estimated.