Does NGC give preferential treatment to the large delaer submitters at the expense of small individual collectors?

I am new member here, but I've already submitted 22 coins for grading. I've been a collector since the early 70s and seen grading standards change with the blowing wind, but I'm wondering if something even more egregious is going on (I hope not, and I look to my fellow memebers to give me their input):

I have some pretty pieces, but when I got these coins back from NGC all of my finest coins -- the ones I was banking on -- came back ONE GRADE out of the money. Now, sure -- maybe I was wrong about two or even three coins, but EVERY COIN?

One coins came back PF66 instead of PF 67 -- a difference in value of $1000. Another two proof coins, vitually identical, came back with one being designated a "Cameo" and the other with no designation. This amounted to a difference in value of something like $3000. I could go on and on.

Is NGC giving dealer-submitted coins the "benefit of the doubt," and putting the screws to the rest of us? I'd really like to know what some of you others thing. Thank you! GREGGSOUND