Generally, allowances are added to normal earnings and the amount to withhold is calculated on the total amount of earnings and allowances. In Guardhouse, you can easily add Allowances applicable to your company.
To set this up, you can go to Organization>>Company>>Payrates>>Pay Categories. You can click Add new to add an allowance category. You would need to fill in the Pay Category Name, Type of Allowance, and the rate.
When you go to the Schedule page and create a shift, you can click show rate details and this window will pop out. You can then add allowance applicable for the shift.
The other option to add this is by going to the timesheet page.You can add it by clicking the Extra's option and this option will pop out.
