We recommend you not to use the same employee ID to log in to the PK4 TimeTracker application at the same time on multiple devices.
We suggest you not use the same ID on multiple devices at the same time is because if the devices are not auto refreshed and synced with the correct Check-In Status. There are chances that you might Check-In for the same Job, again using another device, and there will be multiple time details for you on the same Project at the same time.
Then the Salesforce Administrator will not able to calculate your hours for the payroll. As they will not know the exact hours you Checked-In for a Project.