Rate Budget calculation

Can someone explain how fluxes are computed with the Rate Budget tool?  I have DAC and FEM files provided by a client.  The DAC includes results for selected time steps so I ran the model from the FEM and saved every time step.  Although the hydraulic head distributions appear to be very similar (at least the ones I have compared), I get different results for defined budget groups with the Rate Budget tool at the same simulated time.  The time step history is different for the two simulations (perhaps because the new simulation used version 2.6 of the SAMG solver and the old one apparently used version 2.5).  I am trying to convince myself that the simulation results are equivalent for the two DAC files.  Thanks for the help.

To compare rate budgets between the model runs, you would need to have a complete DAC file with all timesteps saved.

The reason you are seeing different flows at the same modelling times could be due to a shorter or longer simulation time step as the rate budget will apply to that period.