Windows Event Collector

Hello, everyone!

I have an issue about HeartbeatInterval (time:ms) in the WEC. 

This is my configuration file:

-----------------------------------------------------------------------------------------

Subscription Id: customtest1
SubscriptionType: SourceInitiated
Description: Source Initiated Subscription Sample
Enabled: true
Uri: http://schemas.microsoft.com/wbem/wsman/1/windows/EventLog
ConfigurationMode: Custom
DeliveryMode: Push
DeliveryMaxItems: 1
DeliveryMaxLatencyTime: 30000
HeartbeatInterval: 15000
Query:
            <QueryList>
                <Query Id="0" Path="Application">
                <Select Path="Application">*[System[(Level=1  or Level=2 or Leve
l=3 or Level=4 or Level=0 or Level=5)]]</Select>
                <Select Path="Security">*[System[(Level=1  or Level=2 or Level=3
 or Level=4 or Level=0 or Level=5)]]</Select>
                <Select Path="Setup">*[System[(Level=1  or Level=2 or Level=3 or
 Level=4 or Level=0 or Level=5)]]</Select>
                <Select Path="System">*[System[(Level=1  or Level=2 or Level=3 o
r Level=4 or Level=0 or Level=5)]]</Select>
                <Select Path="ForwardedEvents">*[System[(Level=1  or Level=2 or
Level=3 or Level=4 or Level=0 or Level=5)]]</Select>
                </Query>
            </QueryList>

ReadExistingEvents: true
TransportName: http
ContentFormat: RenderedText
Locale: en-US
LogFile: ForwardedEvents
AllowedIssuerCAList:
AllowedSubjectList:
DeniedSubjectList:
AllowedSourceDomainComputers: O:NSG:NSD:(A;;GA;;;DC)(A;;GA;;;NS)

EventSource[0]:
        Address: WIN10.test.test
        Enabled: true
EventSource[1]:
        Address: WIN7.test.test
        Enabled: true
-----------------------------------------------------------------------------------------------------

As you can see HeartbeatInterval is 15000ms (that is 15 sec). 

But when I check the status every 1 sec (wecutil gr customtest1), I see how the status is changed every 5 sec. 

So It should be (that is when we set HeartbeatInternal is 15s, at this time It will check 3 times every 5 sec)?

Or something is wrong in the configurations?