1. In Reservation View there is a checkbox 'Show rates including VAT' if this is checked all rates displayed in the reservation (except the payments summary table were revenue and VAT is always displayed seperately) will be including VAT.
If it is unchecked all rates will be excluding VAT.
2. Also when you edit rates on rooms, extras or services they will be including/excluding VAT depending on the option of the checkbox. It also applies to the prices displayed in 'Add room', 'Date and or Room change'.
3. Note that in 'Add Invoice' and 'Add Payments' you can always see the amount both excluding and including VAT but the 'Amount' field will always include VAT.
4. If you save a reservation the checkbox option you set for this reservation will be saved for next time.