As a system for service-based businesses, we feel the most important elements of the budget for a component are the hours and the service rate. With these, the budget value is easily calculated. The Product is generally not required, and so is explained at the end of this topic.
Service Rate - The drop-down will list components rates and "Any" rates - but not rates for the Issues or Contracts module. If you choose a specific rate, then any time logged on this component will use this rate - regardless of staff rates.
The component total = rate x volume (hr)
Staff Rates - The component total will calculate based on the component assignee. For example, if Peter is the assignee, and has a rate of $150/hr, and 5 hours of service are entered, then the component total will be $750. However, the actual budget usage on the component will vary if staff with a different rate work on this component.


Note: If staff log time against the job itself (rather than a component) then the budget will be consumed using their staff rate. You may want to relocate those activities to correct the budget usage.
Always click Save to apply the changes when editing a component, or Cancel to drop the changes.
If a component includes a fixed cost, or a quantity of products, you can configure this here. If you want to specify that each unit of product comes with 2 hours of service work (for example) you can enter 2 in the credit field. You must enter a product volume of 1 or more for credits to take effect.
Select the hourly rate for this component (or service) and the number of hours provided.
The total will calculate from product cost x quantity, plus service cost, minus any service credits:

In this example, 2 units of $500 gives us $1000 product cost. 4hrs of services at $150/hr gives us $600. 1 hour of credit per product, at 2 products, gives us 2 hours of credit - which is shown on the Service line. So our actual fee for this component is $1600 - $300 = $1300.
The component will still expect that 4 hours of work are logged against it, but when it comes to invoicing, the product cost and credits will be factored in.