When you buy a company vehicle you are most often considering the costs of interest, the residual value, insurances and taxes. You calculate your monthly costs based on these components. All costs like damage repair, maintenance and tires are excluded from the sales price.
If you lease a company vehicle the monthly costs are not only based on costs of interest, residual value, insurances and taxes, but also on the expected costs of damage repairs, maintenance, tyres or time the car spends in the garage. It is all included in the monthly lease price.