ACMI is normally block time so include taxi time, base trip cost on fuel burn from engine start to engine shut down (again include taxi fuel both ends) at planned destination.
As you have it this is an ACMI which would be a total monthly (at a minimum) commitment for the aircraft by another operator (normally) .
If it was a charter the price will be much higher for a one off trip to cover eventualities such as divert, delays etc and for the airline profit margin !!