Why can't modify the vlan aging time

[topnewinfo]

4506-1#sh mac add aging-time

Vlan    Aging Time      Configured Aging Time

----    ----------      ---------------------

Global Vlan Admin Age: 300

   1    300             300

100    300             300

300    300             300

500    300             300

501    300             300

502    300             300

503    300             300

600    15              300

I don't do any aging time Settings, why aging time is 15? I don't have change to take effect.

[Steve Fuller]

Duplicate post of Why cisco WS-C4506-E Switches High CPU?