Thank you for getting back to me.
Your per diem trail was confusing as you stated it.
So let me answer this way.
If you payed your employees perdeim, then on your schedule C that is considered a tax deductible expense.
If you were paid per diem, you can take the expenses you personally incurred, as a deducion, but when you do that, you have to claim the perdeim paid. the effect is you only get to deduct on form 2106 (employee business expenses) that exceed the per diem rate.
Receipts then are required.
You can not subtract rates and deduct those. You can only deduct actual expenses.
so for example. Using the Federal return. If hey paid you 10 cents a mile, but the federal rate were 50 cents a mile, you could claim mileage. You claim the 50 cent rate allowed by the FED on your tax return for a deduction per mile, and then you subtract the mileage you were paid. Your net deducion would be in this example, 40 cents a mile.