Yes, you can use payroll costs from either 2019 or 2020. The guidance describes payroll costs using calendar year 2019 as the reference period for payroll costs used to calculate loan amounts. However, borrowers are permitted to use payroll costs from either calendar year 2019 or calendar year 2020 for their First Draw PPP Loan amount calculation. Documentation, including IRS forms, must be supplied for the selected reference period.