With an OROS 3-Series you get a multi-channel analyzer, so, why not turn your unit into a true multi-channel sound level meter?
Overall Acoustics software module The OVA plug-in complies with the latest sound level meters standards such as IEC 60-672. It runs 3 RMS and a peak detector on each input. The detectors feature time filtering and weighting. Overall levels can be tracked during days in the profiles memory.