As we all have documented there does not seem to be much of a difference other than XP when turning in NQ vs HQ when making airship parts, however I am finishing off our first Invincible Hull II, currently stuck on phase 3 waiting on more Raw Celestine to come back from the current voyage (Comes back @ 9am CST 7/16/15.) I have used 100% NQ turn ins for all 3 phases of this part and the highest construction quality for any phase has been 12/100. It is totally plausible that RNG hated me during this build OR when you reach tier 4 parts the calculations for construction progress does favor HQ mats over NQ mats. Just putting it out there, I will update more as I continue building tier 4 parts. Currently ship #1 is Rank 26 and equipped with a Bronco Hull and the rest are all Enterprise parts (the range would not have allowed me to visit any more islands if I would have went with Enterprise Hull and lowering one of the other 3 parts)