I would probably get all of this outside of the form / list and into its own list. Like - a list that has two columns, one for "Role" (string or choice) and one for "Person" (person or group). You'd have entries like:
| Role |
Person |
| Supervisor |
Jane Doe |
| Technician |
John Smith |
| Technician |
Sue Jones |
| Supervisor |
Bob Roe |
Then, in your form, instead of having to do this kind of conditional logic, you could simply compare to the Role in the list. I'm not quite sure I understand how you are using this default - but if you can take a more data-driven approach, you won't have to deal with this sort of work-around.