Company car tax question

I am currently provided with a company car that my employer leases from another company. They pay for all vehicle related expenses, which is inclusive of gas, maintenance and insurance. Based on my T4, this is Box 34 that is the taxable benefit amount that is added to my total income. To my understanding, this includes both the operating cost (based on per km of personal use) and the standby charge (based on purchase price of the car and how long I had the car available to me). Am I able to confirm with the lease company how they came up with the box 34 value? Is it confidential by any means?

Now, I also contribute about $100 per month via payroll deduction for personal usage of a company vehicle. Is this taken into consideration in the above calculation? Since the amount on my T4 is based on what I provided the lease company (in terms of personal vs business km), I am not sure if this payroll deduction was communicated by my company, or again, if it is even supposed to be. If it's not in this calculation, am I able to claim this anywhere else?

Thanks!