Does changing the default user billing rate affect the user rates defined for different projects?

The billable rate that is defined under a user's profile is the Default value that the system considers when the billing rate type for a user, in a project, is set to User Rate. However, this value is not hard fixed and the system will allow this value to be edited at the project level any time. To track these changes, an effective date can also be provided.

Note:
The User Rate can vary from project to project and any changes to the rate made on one project will not affect the rate on another project.