Employees using the Virtual Terminal to generate bookings can have time disadvantages comparing with the employees generating bookings on a terminal located at the entrance/exit of a building. Grace time corrections are used to compensate this time. These corrections can be made for each booking type (GO, IN, OUT, END) and for each employee.
Go to Configuration - Employees [Edit] - Tab System and set the corrections:
Set up VT grace time correction in Astrow Web Employees [Edit]
If you do not want to use grace, just leave 00 in VT grace time correction fields.