Symptoms:
Users enter 8 hours on the timesheet, however when you run the Timesheet Billing report it just shows 7.47 hours against that user for the whole day. Also the there are multiple rows for the same time entry against the project, even though the user has entered 8 hours in one row for the same project.

Cause:
The Timesheet Billing report will show the data of time entered by users and for billing purposes. The project that you enter time against is a Cost allocation based project. If the cost allocated to all the clients do not add up to 100% then the report will only show the number of hours that are going to be billed to the customer. In this case it will not show 8 hours as the cost allocated adds upto only 93.37% of the total cost, hence the report pulls up only 7.47 hours.
 
Resolution:
In order to resolve the issue you need to ensure that the cost allocation for the project against which time is entered should add upto 100%. Once this is corrected the report will automatically show the correct no. of hours entered by the user.