Time Master will NEVER change records that already exist. For example say in 2012 you were charging a rate of $90/hour. In 2013 you decided to change your rate to $100/hour. If you changed all your rates and all pre-existing records would now be invalid. All your Invoices would now have wrong amounts. So that is why we do not change existing records.
Once you change a rate, whether it is a Global, Client, Project, Task or Custom rate, that rate will only get pulled into a brand *new* Time Entry.
