Kyle Hampton

I'm posting for some clarity on behalf of my partner. He took out a salary sacrifice lease scheme car August 2021. Monthly cost £475 net pay. Contract states yearly gross cost is over 6k. This contract is via a third party and includes insurance, maintenance and servicing but no fuel allowance. What we can't understand is the p11d form the trust has submitted to HMRC is equivalent to £10700 off his personal tax allowance based on a car cost of 33k. What we can't comprehend is why is 10k's worth of tax allowance deducted off when my partner pays 6k a year for the car anyway? There's like a £30-40 saving per month between gross and net pay. Which surely equates to any tax saving costs. Is there an error somewhere in the system or are we not understanding an aspect of the tax benefits allowances with these lease car schemes?