Discrepancy in Indexes

[MAK9974]

I executed all these three statement first
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DBCC DBREINDEX (order_detail, '', 80)
update statistics order_detail
DBCC UPDATEUSAGE ('PCC','order_detail')

when i execute sp_space used the results are
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reserved =805176 KB
data=380048 KB
index size = 424688 KB

Then I executed this
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select * from sysindexes where id = (select id from sysobjects where name = 'order_detail')

The results are strange
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For indid = 1 the RESERVED =100647 KB


when i do 100647 + 380048 = 480695 why not 424688 KB??????

Say I calcluated for 80% index. Now i am calculating for 100% fillfactor

83872.5 + 380048 = 463920.5 KB why not 424688 KB??????


Please guide me.


-MAK