there is no exact numbers, it depends upon case by case and your luck.
So dont think about it, one of my friend who didn't have single LUD on his I485 after first FP also and directly got approved and there are many who got LUD'd 3-7 times.
So its individual luck, once again I am telling all USCIS People and systems are total random in nature.
Good Luck,
rb180
I-485 pending Dec.04
