Sharepoint Configuration Wizard 9 or 10 steps inconsistency

I am not sure why the total steps are different from time to time.

On one server, I installed SP2 and the configuration wizard run 10 steps and failed on 9.  I re-run the wizard and it only had 9 steps and it completed.

On another server. it failed on 9 of 10.  I applied the VM snapshot and installed sp2 all over again. This time, it only run 9 steps and it failed.  then I re-run it.  this time 10 steps and it was successful.