Well, so far all I can gather is that a 'QUI' hasn't completed the full CFS course and been cat'd, so hasn't been trained and tested even to B2 QFI standard?
It is vital that early, formative exercises are correctly taught. A 'QFI' or civil FI(A) has been trained/tested to a known standard - hence any training delivered by such instructors at a UAS may be fully credited towards the NPPL.
Whereas there is no such guarantee with a partly-trained 'instructor'...