How can two employees' with the same rate and same W2 have different tax deducted?

Your confusion ends here, @john-johnhoypain.

Since both employees had the same rate and W2 information, they should have the same tax deduction. To verify, let's review the information on each employee to ensure they are the same. Here's how:

1. Sign in to your QuickBooks Online (QBO) account.
2. Click Payroll from the left menu, then select Employees.
3. Select the employees from the list. 
4. Then, review all the information, including deductions, contributions, and work locations.

If there are information that aren't the same, it's the possible reason why they have different tax deductions.

However, if all the information are the same, I recommend reaching out to our QuickBooks Payroll Team. This way, they can further look into this matter and provide additional troubleshooting steps to get this resolved.

You might want to review your payroll transactions, payroll details, and employees information. There are several payroll reports you can pull up to view such information.

Should you need any additional assistance managing your employees, you can leave a comment below. I'll be sure to get back to you, @john-johnhoypain.