You only claim one way. And I could be wrong but I think you make a voluntary contribution of the first 3 miles ? (someone will correct me I'm sure). I got 13.96 a day for an 86 mile round trip. But remember that you get it every day (365 days a year) and I think it isn't taxed as it's an allowance. I've found that it easily covers my running costs annually but I've got a not very thirsty diesel, it costs me Â£8 a day in fuel and the rest goes towards tax, insurance and the like, plus I only made the trip on average 4 times a week.
Of course, I've probably got it all wrong!
edited to add.......Yes the figure does sound about right.