in the Kaplan text book in chapter 12 pg 332 Test your understanding 4, there is a car benefit and fuel benefit to be calculated for class 1A NIC contributions. the co2 emission is 161g/km diesel car.
so the car benefit % should be 18%+ (160-130)/5 = 24%
however when i looked at the answer they have done 18% + (160-135)/5 = 23% moreover even the fuel benefit base figure taken is 16900 rather than 18000 as done in emp income chapter.
This is an error in the Kaplan kit. Your figures are correct. As you have purchased an exam kit you have access to en-gage which includes an errata sheet Hope this helps