You are correct, NGC is selling a service, would you want you some one selling the same service as you and next to you. That being said, both are grading new coins lower as to get the older coins out in the public for collectors to find them. With all the new coin mints out there with new machines, very few MS 70 still MS 69 are being put in the market, and the low number of MS 70 coins draw a better price. If you have a nice coin just put it up and save it. NGC or PCGS will not make much if your kids have them.