How to understand partition sizes

[Ivan Carey]

Hello,
After installing a new system on a 500Gb HDD the partition size I 
allocated at install does no match the size after complete system 
installation
Disc size comes up as 476937MB

At install I partitioned the disc:
/             2048Mb
/swap     4096Mb
/var        2048Mb
/server   440Gb
/usr        13065Mb

After install and checking the partition sizes with KDiskFree the 
partitions are:
/            1.9Gb
/var       1.9Gb
/server   431.0Gb
/usr       12.4Gb

The /server is 9Gb smaller than I partitioned and the actual free space 
without any files in the partition is shown as 396.5Gb which is another 
34.5Gb smaller.

Am I actually seeing what is really happening or am I really loosing 
43.5Gb of space on the /server partition

Thanks,
Ivan