Can I pay more than the advisory fuel rate?
Yes. A company may set its own rates which can differ from the Advisory Fuel Rate (AFR), and if these rates don't exceed the AFR specified by the government for the engine size and fuel type of the vehicle, there won't be any taxable profit and no Class 1A National Insurance to pay.
If a company's vehicles are more fuel-efficient or if the expense of business travel is higher than the proposed AFR, a company may also choose to set its own rates.
Can I pay more than the Advisory Electricity Rate (AER)?
You can, but it's not always straightforward. If you decide to pay more than the AER, you must provide HMRC with evidence of actual costs, otherwise, the employee and employer could face paying Benefit-in-Kind tax.