Why am i able to make calls more than the quota limit specified?

[archanachowdary]

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Quota async="false" continueOnError="false" enabled="true" name="impose-quota" type="calendar">
    <DisplayName>Impose Quota</DisplayName>
    <Identifier ref="request.header.username"/>
    <StartTime>201-09-19 02:21:00</StartTime>
    <Interval>1</Interval>
    <TimeUnit>hour</TimeUnit>
    <Allow count="3"/>
</Quota>
 
So username "archana" can make 3 calls in an hour,then when i use the trace tool 
and call the api from postman ,I am able to make 5 calls and 6th one is showing 
error.Please refer to images.Why is that?4th call should raise "500" code right?

[anilsr · Accepted solution]

@archana ,

It's due to the number of message processors. Quota counters are not synced by default across message processors. Free trial org by default has 2 message processors. That's the reason you can able to make few calls more than allowed limit.

You can change this behavior by setting distributed & synchronous elements to true in policy XML. More about same you can find in Policy documentation here.

Hope it helps. Keep us posted if any.