It's a wash. There are three parts.

The operations and ownership of the vehicle is 100% business. That's the gross deduction.

The value of the use to the employee is a taxable benefit. But to avoid paying it out as real takehome, there is the addition (so it is taxed) and then the Net is a deduction from the paycheck. And that deduction is the offset for the vehicle use, a contra-expense, or into a benefit expense category.

The deduction is the offset.