Calculate the volume delta and assess its reasonability

After the volume counter from the rate record is read, the volume delta (volume change) from the previous counter to the new counter is calculated. If there is a last good counter that differs from the previous counter, then a second volume delta from the last good counter to the new counter will also be calculated.

Once a volume delta is calculated, the Virtual Flow Computer (VFC) processor determines whether the delta is unreasonable (too large to be realistic and possibly caused by bad telemetry) or reasonable.