Thanks for joining in this thread, Clinician.
I'm here to help you go over to your employee's set up to accrue the PTO for commissioned employee via QuickBooks Desktop.
As referenced by our Community Backer BRC above, it works the same with as an hourly or salaried employee. To accrue the PTO credits for the commissioned employee, you'll need to choose the Every hour on a paycheck for the Accrual Period.
To create a paycheck for the commissioned employee:
You can get more details in this article: https://community.intuit.com/articles/1763467-set-up-and-pay-sick-and-vacation-time.
Should you need more help in accruing PTO for the commissioned employee, please let me know. I'm always here to help you out.