[squid-users] Zeroed SNMP statistic after reload

I experiment with use SNMP for limited client traffic in real time.
I have problem with zeroed values SNMP after /etc/init.d/squid3 -k
reload (time to time). Before reload I do "/usr/sbin/squid -k check"
and do not have any errors or warnings.

I understood command "restart" does zeroed values SNMP, but "reload"
does not. In what case SNMP statistic will be cleaned after reload?

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SQUID 3.1.8
Linux Debian 7.2
Best regars,
Kirill