More tax than expected on employment when completing self assessment (company car)

Hi, I've just completed a draft of my 23/24 self assessment tax return online. I'm employed and received property & savings income. My calculated tax bill is significantly higher than expected. The tax for my property & savings income is correct and as expected, so the issue must be coming from employment. When viewing the calculation generated by HMRC, I can see that my company car and private medical P11D values are being added back on to my employment income, which seems to be throwing things out. Why is this happening? Both benefits are salary sacrifice and I have already been taxed for these via a change to my tax code throughout the year. I'm unsure why I would've been paying the incorrect tax during the year through employment. I have not been notified that I've paid the incorrect amount of tax for the year. Please could someone advise? Much appreciated.

Hi,
If your company car and private medical insurance are paid by salary sacrifice, you do not need to declare these on your tax return, if you do, they will be included in your calculation.
If you have submitted your return, you can reopen it through your personal tax account and remove these figures, or contact our Self Assessment team so we can amend your return as necessary.
Self Assessment: general enquiries
Thank you.