How do you handle mileage reimbursements, which are often based on gas prices, for employees who drive electric vehicles?

Curious for thoughts …
Regional managers normally get mileage and/or a vehicle allowance for travel throughout their portfolio. This is usually based on IRS rate and is established based on gas prices
If the employee has an electric vehicle- should they be getting the same, or would it be most appropriate to give an electricity allowance to offset the additional electrical cost at home for driving more for work?

If you get comped above IRS rate that is taxable fringe.
You get paid a standard rate because it is impractical to calculate depreciation, fuel, tires, maintenance etc for 200 different types of cars trucks suv scooters atv or ev.

I guess my question would be why should the company change their payments for the type of vehicle the associate decides to buy? Now if the company is not paying an allowance because the associate has an electric car then that's an issue in my opinion.

Our company pays the same for all vehicles

We get a flat rate monthly. So you can use it as needed. I used it to justify a higher car payment so I could buy a PHEV ?