No, the estimated value of the commodity for which you are seeking an advance cannot be appealed. The value of your advance is based on your estimated production multiplied by the commodity value as determined by the federal government and limited to your security (i.e. AgriInsurance, AgriStability).
If an administrator feels that the advance rate per production unit is incorrect, they can request that the Minister review the advance rate. The administrator would likely be asked to support any increase in advance rate by providing reliable market data.