Bukkit

NOTE: If you supply copies of your .yml or console log files, please use pastebin, dropbox, or other service and provide link,  instead of copy/paste of the file into this report. Thanks!

What Version of OnTime and Bukkit are you using?
OnTime: OnTime v3.13.3
Bukkit:

What storage option are you using? (YML or MYSQL) ?
YML
What permissions plugin are you using? (Groupmanager, PEX,bPermissions, etc.)
PEX
Please provide a link to a copy of your plugins/OnTime/config.yml:

http://pastebin.com/download.php?i=QkCm2jM2
What steps will reproduce the problem?

1. Player gets demoted on leave
2. Player get promoted on join (based on hours)

What is the expected output? What do you see instead?
Player to stay the same rank, players get demoted and promoted, again and again

Do you have an console log of what happened?
no errors
Are you having a "rewards" problem?  Please provide a link to a copy of your /plugins/OnTime/rewards.yml :
play time rewards: http://pastebin.com/download.php?i=hSK7wpEP
Did you turn on OnTime logging (/ontime logfile enable 1)?  If so, provide a link to that file too.

Please provide any additional information below.

Please turn on OnTime logging and capture an occurrence of the issue you are seeing.

Turn on with

/ontime logfile enable 1

Then post a link to a copy of the resulting OnTimeLog.txt file