Ensuring a smooth shift in pay periods is my primary goal, Joey. Maintaining consistency in your payroll processing is crucial, and I'm here to assist you in executing it.
The issue you're experiencing arises because you have set up a monthly payroll schedule that spans 30 days. In QuickBooks Online (QBO), we cannot customize the pay period to fit your needs beyond the standard options. Therefore, I recommend adjusting the regular pay for the period to avoid overpayments. Refer to the screenshot below for reference:

Additionally, you can only set up one pay schedule for a single employee in the software. Hence, I suggest creating a paycheck for the current coverage period before establishing the new pay schedule for a smooth transition.
For detailed steps, here's how:
- Go to the Payroll section, then select Employees.
- Click Run Payroll.
- Ensure that the Pay period and Pay date are correct.
- Choose the employees you wish to include in this payroll run.
- Click on the column for each employee or select Actions, then Edit paycheck to enter your pay details.
- Select Preview Payroll to review all details before finalizing.
- Choose the bank account you want to track the payroll expenses.
- Click either Preview payroll details or directly on Submit payroll, then select Close.
Furthermore, you can refer to this article if you create paychecks outside of QuickBooks in the future: Manually enter payroll paychecks in QuickBooks Online.
Consider this channel your go-to resource for any QuickBooks Payroll inquiries. Whether you need assistance with pay schedules or running payroll reports, we encourage you to revisit this thread or create a new post. Our team is always ready to support your business needs.