You can override the content of each automatically generated invoice line. You can also enter details for an ad hoc line after clicking:
•Add to create a blank line at the end
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or 
to insert a blank line above or below the current one
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to delete the current row.
For each existing or blank line, enter or select:
•Contract Line/PO are selected as a line from the project’s contract and one of the line’s purchase orders
•Type is preset as ‘Other’ for a manually added ad hoc line or will be ‘Time’ or ‘Expense’ in other cases.
•Description defaults from the contract line but can be changed for each invoice.
•Units will generally be the number of hours that is being charged or will apply for unit-based expenses. Input is not relevant for ad hoc lines.
•Net Charge is calculated as the input number of units multiplied by the contract charge rate for time and expenses but does not apply for ad hoc lines. For a fixed price contract line, the specified cycle value is shown here providing it has not already been invoiced in the period. For capped charges, the calculated amounts may have limits imposed due to billing rules.
•Adjusted Charge is entered as the charge value for an ad hoc line. In the case of time and expenses, any value input here will override the calculated net charge. This includes the ability to override fixed charges or enter them if not specified on the contract line. Click 
to calculate the charge as units multiplied by unit price.
•VAT/Tax % defaults from the billing contract but can be overridden for each line.
•Gross Charge is calculated automatically by adding VAT at the specified rate to the net or adjusted charge.
Click Update to recalculate any added or amended line. Any updates will also change the This Invoice block by altering the values to be charged this time and the remaining value under the terms of the contract.