For a sole proprietor, with a solo 401k that permits —
– Non Roth After Tax Contributions
– In Plan Roth Conversions

there is the extra calculation From Net Self Employment Earnings to calculate — “Amount Taxable for the Self Employment Tax”.

Is that the base figure to subtract —
Deferrals
Employer Contributions

in order to arrive at an amount available for the After Tax Contributions?

Below is an Example: Self Employed Person / age 60 with Net Income of $60,000

Example:
Net Self Employment Earnings $60,000.00
Amount Taxable for SE Tax 55,410.00
50% of Self Employment Tax 4,238.87

Adjusted Earned Income 44,609.00 net Profit after SE Taxes and Employer Contribution
Annual Contribution % 25%
Employer Contribution 11,152.00
Deferral + Catch Up 24,000.00
Maximum Ceiling 60,000.00 415(c)-1(a) limit
Max Deductible 35,152.00 (24,000 + 11,152)

Amount Available for
After Tax Contributions 20,258.00 55,410 – (24,000 + 11,152)

Is my thinking correct??