SBC SNMP QoS value received equal to zero

Hello all,

We have observed that SNMP response from a 3820 running 6.3.7 for apSigRealmStatsAverageQoSRFactor inquiry was a value equal to zero (0.00 preciselly) from a realm without traffic. Other realms with load show values like 93.00 or 82.00, which look actual accurate values, as calls sound well. The question is: what does the zero value answer mean? Does it mean that, as there is no traffic, the value is null? Should this value be ignored in a monitoring tool in order to avoid spikes or a zero level values? Is this behaviour explained on documentation? Where?

We have doubts about if is it possible such low value, as graphics from R-Factor degradation along PPL or latency fall until an asinthotic limit that seems never is below 10 or similar but alwayw far away from absolute zero.