When is an estimate accurate?

I've been with NGC for a couple of years and am wondering if I just have bad luck or are tohers finding the same thing - I never get a coin in the listed turnaround time. I have submitted coin US, world & ancients, I have sumitted medals and tokens, I used to submit a lot of errors, but nonr ever came or even was moved from scheduled for grading in the actual turnaound times listed (which are always longer than the 'regular' times). When I get my 'free' submissions with membership every time it has taken months and months on early bird submission. I sent one at two day turnaround and $125 fee that took six months. Has ANYONE ever gotten a coin back in the times listed? please tell what service level and your experiences to help me in the future. I have bought ungraded coins on ebay and never get them back in time to file buyers protection if there is a fake, cleaned or other issue.