Each report has its own parameters, most of which are common to all reports. These are normally set using the report's selection criteria window and is different for each one.
You can override a report's selection criteria by adding parameters to a special section in the main configuration file. This means that, although a user may set a specific parameter in the report selection criteria window, it will be overwritten by that set in the main configuration file. This allows you to fix certain settings, for example the 'percentage mark-up' in a billing report.
Each report has its own ID number - the billing report has an ID of 2. This corresponds to the setting in the main configuration file that you need to alter.
As an example, let's fix the % mark-up in every billing report to 50% and set the surcharge to £1.00.
Edit the main configuration file via the Set-up screen, and in the section entitled [Report Customisations], add or amend the line Report2Extra to read:
Report2Extra = &markup=50&surcharge=1.00
From now on, when a billing report (ID = 2) is run, these extra settings are forced upon the reporting engine and override any values that the user selected.