For tip transaction Source Type will be Employees Account and Target Type will be Receivables. Default target will be also Receivables.
Untick Toggle Calculation for calculation type.
Additionally you need an employee entity type, entity type’s account type will be Employees Account and you should map that entity type to ticket type.
You’ll create employee entities for each employee and map their accounts.
At the end of it when you select an employee for ticket tip calculation will be added to employee’s mapped account.