Hi there kelly155,
It's important that all your transactions be entered correctly so that your pay is accurate. QuickBooks Online payroll is a great tool able to calculate pay for hours worked. I can point you in the right direction to modify deduction amounts when running payroll.
When running payroll, if you want to adjust the number of deductions, you can click on the pencil icon beside the employee in question, then you can click on the Employee deductions, and Employer contributions sections in order to adjust the amount of those deductions to the one you wish it to be.
if you have any other questions, feel free to reach out here.