Titan, like most solvent charter operators, don't do it that way. They charge a daily fixed rate which covers cost of aircraft, crew, contibution to overheads/profits and then an hourly rate which covers their variable costs (mainly engineering). Their hourly rate may also include fuel but often the customer airline picks that up along with all the third party user and handling charges. Whole plane charters for non-aviation customers are priced in a similar way; this emans that if they fly they are making money.
I hope this helps.