This is strange to me. Any car share (Turo or any rental service) self-employed person should be able to do standard mileage  deduction and back off fuel costs easily WITHOUT receipts. For example if you have a vehicle that has 10k business miles and you’re claiming standard mileage deduction of 57.5 cents thats a deduction of 5750. Couldn’t you simply take the fuel range of the car (ex 400 miles) divide the total mileage by the cars range and divide that to determine how many tanks of fuel, in this case 25 and then multiple that by the fuel capacity of the tank (ex 23 gallons), finally multiply by the average cost of fuel (ex 2.50) which gives us $1437 and then deduct that from the total “standard mileage deduction” so $5750-$1437= a total deduction of $4313. I’m not an accountant or a cpa but is there any reason this is NOT an acceptable way to go about this?