A computer implemented data processing system and method administers a deferred variable annuity contract during the accumulation phase for a relevant life. The annuity contract has a payment base value, a contract value, and benefit payments. A maximum annual benefit payment withdrawal amount available without reducing the payment base value is calculated by multiplying the payment base value by a factor including a deferral bonus percent, which is a function of a number of years deferred by the relevant life until taking a first lifetime benefit payment.