Fluid level measurements for the shared tank and outflow information provided by calibrated flow meters corresponding to dispensing stations connected to the shared tank may be used to derive a filled volume model for the tank as a function of fluid level. Subsequently, a filled volume change for a shared tank over a selected time interval may be determined from pre-change and post-change fluid level measurements. The change in filled volume may be compared with the total fluid flow over the selected time interval as indicated by the flow meters of active dispensing stations. If the filled volume change for the tank is substantially different than the total fluid flow indicated by the flow meters, the flow meters may be collectively adjusted to provide a more accurate indication of the filled volume change in the shared tank.