This field cannot be accessed when the "Expense invoicing terms" field includes the "Charges included" note.
If the "Expense invoicing terms" field includes the "Fixed-cost" note, this field is then used to enter the amount of the fixed-cost contract applied for each invoice.
If the "Expense invoicing terms" field includes the "Actual mileage" note, this field is then used to enter the amount applied for each kilometer/mile travelled.
If the "Expense invoicing terms" field includes the "Actual time spent" note, this field is then used to enter the amount applied for each hour elapsed and started.