Hi swoodman, we'll have to follow specific processes to deduct it from income tax due.
 
It good that you've successfully set up CIS in your books. Now, take the next step by manually inputting the contractor's information from the monthly CIS statement. Afterward, generate an invoice or sales receipt to document the payments received from contractors. To complete the process, I recommend checking this article for more details about it: Use the CIS feature in QuickBooks Online. 
 
If you need assistance with specific tax implications or seek further customization based on your needs, you can consult your accountant. They can offer alternative approaches or methods for deducting it from your income tax due.
Feel free to ask if you have any further questions regarding recording data in QBO.