You have to Read the pop up, in Edit Payroll Item.

If you edit a Payroll Compensation or other Addition/Deduction, it states “Affected By This Item.”

If you edit a Tax item or other computing item, it states “Select the Items Subject To” this tax or computation item.

So, they mean different sides […]

Resolution for 'computing item issue: 'When setting up 401k or 401k Roth payroll deductions, why does Quickbook default incorrectly? It has Federal and State taxes checked for 401k and unchecked for 401k Roth.' available: Yes.

The computing item issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the computing item issue yourself by looking for a resolution described in the article. If it is a complex computing item issue or you are unable to solve the issue, you may contact us by clicking here or by using other computing item support options.

For more information about resolving issues related to computing item in Quickbooks/QBO or to get support for the issue 'When setting up 401k or 401k Roth payroll deductions, why does Quickbook default incorrectly? It has Federal and State taxes checked for 401k and unchecked for 401k Roth.', click the link below: