Yes, the AQ5 has all that calibration stuff in there. Flow meters are more of a luxury item than being necessary, but I do like having some sort of relative reference when not regularly servicing a loop. I noticed in my two year setup, my flow meters very slowly went down from about 1.15GPM to 1.0 GPM or so, so it was an indicator that a little bit of crud was building in the CPU block. That's really the only benefit I see beside using one for testing purposes.