wcf service : getting early timeout exception before send timeout specified

Hi All,
I have a wcf service for which we have given the "send timeout" as 200ms but when we are calling the method of that service,the following error is
"has exceeded the allotted timeout of 00:00:00.1680000. The time
allotted to this operation may have been a portion of a longer timeout. The operation has timed out"
 
Here the alloted timeout is showing as "168ms" while we have mentioned the send timeout as 200ms in the configuration.
 
The bindingconfigutation is as follows:
 

<binding name="TestBinding" maxReceivedMessageSize="2147483647" closeTimeout="00:00:00.200" maxBufferPoolSize="2147483647" messageEncoding="Text" textEncoding="utf-8" openTimeout="00:00:00.200" receiveTimeout="00:00:00.200" sendTimeout="00:00:00.200" >
          <readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="4096" maxNameTableCharCount="16384" />
          <security mode="Transport">
            <transport clientCredentialType="Certificate" />
          </security>
        </binding>

 

 
Not sure why the service is timing out before specified timeout. Any help would be appreciated.
 
Thanks in advance,
Manisha