This idea has been tossed around and let me just state its not true

the SP itself is random between a certain range, and after having done 10s of thousands of synths, with and withoiut HQ mats i can tell yuo right now, the quality you end up with has no bearing on SP gained.

your results are more likely in/out of fatigue.

im doing scale bugs right now

i get 450-550 for NQs
i get 450-550 for HQ1s
i get 450-550 for HQ2s
i get 450-550 for HQ3s