[dnsdist] Difference in stat between pdns and dnsdist

[dims]

Hello
We compare statistics between pdns (pdns-static-3.4.8-1.x86_64) and 
dnsdist (dnsdist-1.0.0-1pdns.el6.x86_64)
This stat from one server we collect stat per hour:
pdns stat more smooth and pps is bigger than in dnsdist 
https://scr.pics/Polzovatelskie_grafiki_obnovlenie_kazhdye_300_sek._2016-04-28_10-46-34.png
dnsdist stat more sharp and pps is less than in pdns 
https://scr.pics/Polzovatelskie_grafiki_obnovlenie_kazhdye_300_sek._2016-04-28_10-48-39.png

In pdns queries and response the same (maybe 1-5 pps difference)
In dnsdist difference is big
queries                       179148
responses                     102344

pdns stat from pdns_control
dnsdist stat from echo "dumpStats()"|dnsdist --client

Counters refresh by zabbix every 30 seconds

Whose statistics more correct?

Config:
controlSocket("127.0.0.1")
setKey("********")
newServer({address="*.*.*.*", name="***", qps=2000, order=1, weight=1, 
checkName="domain.name.", checkType="A", maxCheckFailures=1, retries=5})
newServer({address="*.*.*.*", name="***", qps=2000, order=2, weight=2, 
checkName="domain.name.", checkType="A", maxCheckFailures=1, retries=5})
newServer({address="*.*.*.*", name="***", qps=2000, order=3, weight=2, 
checkName="domain.name.", checkType="A", maxCheckFailures=1, retries=5})
setServerPolicy(firstAvailable)
addLocal("0.0.0.0:53", true, true)
addLocal("0.0.0.0:53", true, true)
addLocal("0.0.0.0:53", true, true)
addLocal("0.0.0.0:53", true, true)
setACL("0.0.0.0/0")
pc = newPacketCache(10000, 86400, 0, 60, 60)
getPool(""):setCache(pc)
addAction(AndRule({makeRule("0.0.0.0/0"), NotRule(MaxQPSRule(1000)), 
TCPRule(false)}), TCAction())
setVerboseHealthChecks(true)
setMaxUDPOutstanding(35535)