Date Faceting or Range Faceting with offset doesn't convert timezone

I am trying to facet based on date field and apply user timezone offset so that the faceted results are in user timezone. My faceted result is given below,

<?xml version="1.0" encoding="UTF-8"?>
<response>
<lst name="responseHeader">
<int name="status">0</int>
<int name="QTime">6</int>
<lst name="params">
<str name="facet">true</str>
<str name="q">icici</str>
<str name="facet.range.start">2011-05-02T00:00:00Z+330MINUTES</str>
<str name="facet.range">createdOnGMTDate</str>
<str name="facet.range.end">2011-05-18T00:00:00Z</str>
<str name="facet.range.gap">+1DAY</str>
</lst>
</lst>
<lst name="facet_counts">
<lst name="facet_ranges">
<lst name="createdOnGMTDate">
<lst name="counts">
<int name="2011-05-02T05:30:00Z">4</int>
<int name="2011-05-03T05:30:00Z">63</int>
<int name="2011-05-04T05:30:00Z">0</int>
<int name="2011-05-05T05:30:00Z">0</int>
......
</lst>
<str name="gap">+1DAY</str>
<date name="start">2011-05-02T05:30:00Z</date>
<date name="end">2011-05-18T05:30:00Z</date>
</lst>
</lst>
</lst>
</response>

Now if you notice that the response show 4 records for the 2th of May 2011 which will fall in the IST timezone (+330MINUTES), but when I try to get the results I see that there is only 1 result for the 2nd why is this happening.

<?xml version="1.0" encoding="UTF-8"?>
<response>
<lst name="responseHeader">
<int name="status">0</int>
<int name="QTime">5</int>
<lst name="params">
<str name="sort">createdOnGMTDate asc</str>
<str name="fl">createdOnGMT,createdOnGMTDate,twtText</str>
<str name="fq">createdOnGMTDate:[2011-05-01T00:00:00Z+330MINUTES TO *] </str>
<str name="q">icici</str>
</lst>
</lst>
<result name="response" numFound="67" start="0">
<doc>
<str name="createdOnGMT">Mon, 02 May 2011 16:27:05+0000</str>
<date name="createdOnGMTDate">2011-05-02T16:27:05Z</date>
<str name="twtText">#TechStrat615. Infosys (business soln & IT
outsourcer) manages damages with new chairman K.Kamath (ex ICICI
Bank chairman) to begin Aug 21.</str>
</doc>
<doc>
<str name="createdOnGMT">Mon, 02 May 2011 19:00:44+0000</str>
<date name="createdOnGMTDate">2011-05-02T19:00:44Z</date>
<str name="twtText">how to get icici mobile banking</str>
</doc>
<doc>
<str name="createdOnGMT">Tue, 03 May 2011 01:53:05+0000</str>
<date name="createdOnGMTDate">2011-05-03T01:53:05Z</date>
<str name="twtText">ICICI BANK LTD, L. M. MIRAJ branch in SANGLI,
MAHARASHTRA. IFSC Code: ICIC0006537, MICR
Code: ...
http://bit.ly/fJCuWl #ifsc #micr #bank</str>
</doc>
<doc>
<str name="createdOnGMT">Tue, 03 May 2011 01:53:05+0000</str>
<date name="createdOnGMTDate">2011-05-03T01:53:05Z</date>
<str name="twtText">ICICI BANK LTD, L. M. MIRAJ branch in SANGLI,
MAHARASHTRA. IFSC Code: ICIC0006537, MICR
Code: ...
http://bit.ly/fJCuWl #ifsc #micr #bank</str>
</doc>
<doc>
<str name="createdOnGMT">Tue, 03 May 2011 08:52:37+0000</str>
<date name="createdOnGMTDate">2011-05-03T08:52:37Z</date>
<str name="twtText">RT @nice4ufan: ICICI BANK PERSONAL LOAN http://ee4you.blogspot.com/2011/04/icici-bank-personal-loan.html </str>
</doc>