Mileage doesn't over tires, oil, wear and tear. Gas is expensive too. Management please listen..car allowance with mileage, a paid vacation...something. Yes, I am grateful for having a job but sometimes feel taken advantage of.
Mileage at $0.565 does cover maintenance. If you drive 12,000 miles per year for your job, you get reimbursed $6,780.
If you opted for a an allowance of 3/5 (or 60%) of a generous allowance of $600 per month (because you have a 3 day work week instead of a 5 day work week) then your allowance would be, at most, $360 per month, or $4,320 per year. If you drove that same 12,000 miles, with a mileage reimbursement of $0.19, your mileage reimbursement would be $2,280. So, the allowance at $4,320 plus mileage of $2,280 would equal $6,600.
At 12,000 miles, you lose $180 with an allowance. At 15,000 miles, you lose $1,305. If you only drive 10,000, you are better off with an allowance by $570. But overages for auto allowances are taxable outside a range, as anyone who has received an allowance and driven few miles knows.
That is the math. The advice above to seek guidance on what to do with taxes is well taken. Nothing is tax free. Anyone who believes they can receive an auto allowance and mileage reimbursement without reporting them as reimbursed expenses while still taking the $0.565 rate would be incorrect. If you are audited and believe the allowance and mileage reimbursement is free money, but the milage deduction is okay to take, hope you don't get audited, or for a forgiving auditor if you do.
The simple answer is, the most fair and generous reimbursement structure is the mileage reimbursement at the federal rate of $0.565. The company is not obligated to that by law, by the way. They could pay much less per mile and let you figure it out on your taxes.
With the current structure, the more you drive, the better off you are without an allowance. That covers the wear and tear and depreciation. If you drive very little, then you don't need to worry about that as much.
As for paid vacation, it depends on how you want your money delivered, either maximum money allowed by contract for the hours you work, or a lesser amount per hour with a built in vacation. It is a zero-sum equation. There is a very specific amount of money to pay us for what we do. Moving the money around into different buckets with different labels doesn't do anything useful, but maybe psychologically it would be nice. I would rather get another raise!