Message Search API not returing all messages within a date range

Hi Lithium Experts,

I am working on a connector that retrieves all the messages from the Lithium Forum (within a date range) and process it as per the business needs.

But when I try to retrieve the messages within a date range, I do not get all the messages that are posted within that date range.

For instance, here is one message

http://h30434.www3.hp.com/restapi/vc/messages/id/5176193

The above message was posted on 2nd August 2015

<post_time type="date_time">2015-08-02T09:01:56+00:00</post_time>

Similarly, there is another message

http://h30434.www3.hp.com/restapi/vc/messages/id/5176160

The above message was also posted on 2nd August 2015

<post_time type="date_time">2015-08-02T08:00:28+00:00</post_time>

However, when I perform a search on messages through the API, I get only one result.

Here is my API call

http://h30434.www3.hp.com/restapi/vc/categories/id/Notebook/boards/id/Laptop-Freeze/search/messages?q=date:[1438473600%20TO%201438675205]&sort_by=date&restapi.format_detail=full_list_element&page=1&page_size=1000&restapi.response_format=json&restapi.response_style=view

Can you please let me know what I am missing in my API call.

Thanks & Regards,

Deepak.S