Words are the things that make confusion...
Be careful. A flight test for the purposes of defining or proving the airworthiness of an aircraft is different than a flight test of a pilot for the purposes of obtaining a licence. Both are called flight tests.
The flight test for a new type of aircraft in development is called the same thing as the flight to prove that an aircraft coming out of maintenance performs as it should. Same name.
Regulations or policy that call these things the same name are bound to create confusion.
I've seen an agency that had a 'Certification' branch that did nothing by grant licences to pilots- their claim was that they were certifying pilots... (as opposed to airworthiness certification, which another branch of the same agency did).
May I suggest that the term 'post maintenance check flight' be adopted for those flights, and 'developmental' or 'experimental' or 'certification flight test' be used for those flights. I'm not sure what to call the flight that a pilot would do for licencing purposes - a check flight?