Metricbeat not accurate the value

Hi can i know why the pid value is different in linux is 166 but in kibana showing 117

[ps aux | wc -l
166

Also

              total        used        free      shared  buff/cache   available
Mem:           3789         490        2729          11         569        3069
Swap:          3275           0        3275

But my kibana showing 719 MB