What does work, extra, benefit, expense, and refund mean?
Work: This is the payment you receive for the work that you have done
Extras: This is payment you receive on top of the work. i.e. tips
Benefit: This is in case you receive any additional benefit payment (Items such as taxi fare outside of work hours, gifts, or other items received by employer that is not directly related to a work situation. In Norway, such items are taxable.)
Expense: This is any costs associated with the job that should be refunded in full. This can for example be costs related to travel.
Refund: Money that is refunded, i.e. that is paid back to you for one reason or another. For instance, this could be when you pay a sum to borrow some equipment for the job, and you get the money refunded when returning this equipment.