Unfortunately, HMRC is unable to provide specific or tailored advice through the Online Community Forums and cannot comment on any form of calculation, example or scenario as we may not be in possession of all the relevant information.
While the HMRC Customer Forum is for general queries only and is intended to help our customers self-serve and we are unable to provide financial advice or further interpretation of the guidance provided on GOV.UK. you may find the following of some use:
Adjusted net income is your total taxable income before any Personal Allowances and less certain tax reliefs*. You can find more details, and work out your adjusted net income here:
https://www.gov.uk/guidance/adjusted-net-income
Personal Allowances: adjusted net income - GOV.UK (www.gov.uk)
* This may include your pension, but does not include Income Tax and National Insurance.
If your employer deducts the pension contributions from your gross pay before tax is calculated then you would not deduct again for the adjusted net income.