i have luck to max 5  

and i have been grinding (same spot)1  day one moster is A knowledge and other S knowledge i have  50% drop rate (from sever)plus node lvl 2 5% plus a scroll 50%  drop rate can get once awhile I get green loot armor or weapon  in a  area is for 90-120 . am I doing something wrong I can't even get a blue loot for weapon or armor.

https://grumpygreen.cricket/bdo-grinding-spots/

If by quality drop rate you mean accessories and such, I'd say about 0.01% or so but it depends on the mobs and their drops. Witch's earring seems far more common than serap necklace even tho nagas drop far more trash loot.