An Actual Expense is created by having Payroll; payroll is a Cost for time spent, for purposes of th business expense.
If the tax entity type is not a corporation, you are not on payroll, so there is no Cost for your time. What you are asking about is a Forfeit of Sales Gross, the same as a Discount or write off. You can either Not show the customer, or Charge them and then write it down (discount or negative entry, for an adjustment, or credit memo).
Example: I work for a charity and charge them 4 hours, but I write off 2 as "my gift to you." That is part of Sales, not Expense. There is no Actual Expense for my time.
Otherwise, what would prevent you from reporting on your taxes that you Wrote Off 500 hours as Expense?