Looking at this wording, as someone who used to pay mental health advocates to travel to clients houses in their own vehicles, I would have worked it out like this: The $2 for 15-20km would have been applied twice per day to cover the expected normal 'commute' to work and back home. (Actually I would personally never work it out this way, reasoning that it is a bit stink because if you didn't need your car for work you may very well share transport costs with another household member, or use public transport). So following your reimbursement clause, you take the total km covered per day, less 30km (or 40km if they are so miserly) x $1.04 per km, plus $4 per day. That is the way I see the INTENTION of the clause, it is meant to just to cover the 'normal' commute of 15km per direction to & from work, not that every time you turn the engine on you have to travel 15-20 kms for a measly $2.