This paper contributes to on-going empirical search for an appropriate crude oil price benchmark that ensures greater financial stability and efficient fiscal management in Nigeria. It adopted the seasonally adjusted ARIMA forecasting models using monthly data series from 2000m01 to 2012m12 to predict future movement in Nigeria crude oil prices. The paper derived a more robust and dynamic framework that accommodates fluctuation in crude oil price and also in government spending. The result shows that if the incessant withdrawal from the ECA fund and the increasing debt profile of government in recent times are factored into the benchmark, the real crude oil numerical fiscal rule is (US$82.3) for 2013 which is higher than the official benchmark of $75 used for 2013 and 2014 budget proposal. The paper argues that the current long run price rule based on 5-10 year moving average approach adopted by government is rigid and inflexible as a rule for managing Nigerian oil funds. The unrealistic assumption of the extant benchmark accounted for excessive depletion and lack of accountability of the excess crude oil account. The paper concludes that except the federal government can curtail its spending profligacy and adopts a more stringent fiscal discipline rules, the current benchmark is unrealistic and unsuitable for fiscal management of oil revenue in the context of Nigerian economic spending profile.