Like already reported, the field ordering is not working correct.
I tried to resort the fields in the backend, but they are not ordered like they should. I tried to order them by moving the field here:
/administrator/index.php?option=com_dtregister&controller=field
This page also show the right ordering when I sort it.
But in frontend (eventbooking) & in backend ( for example administrator/index.php?option=com_dtregister&task=edit&controller=user&cid[]=3563) the ordering / sorting is different.