gcc reinstallation

Hi all,
I'm trying to reinstall gcc package,
can any body explain to me why is the difference in size while the packages names is the same
[root@localhost documentation]# yum upgrade gcc
Loaded plugins: aliases, changelog, downloadonly, fastestmirror, filter-data, keys, kmod, list-data, protect-packages,
              : protectbase, security, tmprepo, verify, versionlock
Loading mirror speeds from cached hostfile
 * addons: ftp.linux.org.tr
 * base: ftp.linux.org.tr
 * centosplus: ftp.linux.org.tr
 * extras: ftp.linux.org.tr
 * rpmforge: fr2.rpmfind.net
 * updates: ftp.linux.org.tr
Skipping filters plugin, no data
0 packages excluded due to repository protections
Skipping security plugin, no data
Reading version lock configuration
Setting up Upgrade Process
No Packages marked for Update
[root@localhost documentation]# yum reinstall gcc
Loaded plugins: aliases, changelog, downloadonly, fastestmirror, filter-data, keys, kmod, list-data, protect-packages,
              : protectbase, security, tmprepo, verify, versionlock
Setting up Reinstall Process
Loading mirror speeds from cached hostfile
 * addons: ftp.linux.org.tr
 * base: ftp.linux.org.tr
 * centosplus: ftp.linux.org.tr
 * extras: ftp.linux.org.tr
 * rpmforge: fr2.rpmfind.net
 * updates: ftp.linux.org.tr
0 packages excluded due to repository protections
Reading version lock configuration
Resolving Dependencies
--> Running transaction check
---> Package gcc.i386 0:4.1.2-46.el5 set to be updated
---> Package gcc.i386 0:4.1.2-46.el5 set to be erased
--> Finished Dependency Resolution

Dependencies Resolved

==============================================================================================================================
 Package                  Arch                      Version                              Repository                      Size
==============================================================================================================================
Installing:
 gcc                      i386                      4.1.2-46.el5                         base                           5.2 M
Removing:
 gcc                      i386                      4.1.2-46.el5                         installed                      9.6 M

Transaction Summary
==============================================================================================================================
Install      1 Package(s)        
Update       0 Package(s)        
Remove       1 Package(s)        

Total download size: 5.2 M
Is this ok [y/N]: n
Exiting on user Command
Complete!