For services that are defined as Time and materials, you can define a fixed cap which will then determine the maximum price that can be charged to the client, regardless of the hours put in.

To establish a maximum charge, start by configuring the billing type to Time and materials and defining the price and quantity for the service in the Budget editor.

Then, open the three-dot menu next to the service section name and from the menu options, choose "Show fixed cap".

Once activated, a padlock icon will be displayed beside the Time and materials service line items. Click on the padlock to activate it (turning it violet), preventing charges beyond the defined service total from being invoiced to the client.

Ensure that the changes are saved to complete the setup process.

After saving the changes, the activated padlock will be visible next to the Time and Materials line items you've set.