Even if Ames is selling the Parts Place products, IMO you would still be better off buying through Ames just in case you are not happy with the item and or have a problem. At least you know Ames will stand behind it and take car of you. Whereas with the Parts Place I'm not so sure that will be the case.
Ames has never done me wrong in the nine years I have been buying from them. In one case with a pair of exterior door handles they pitted only after a year on the car. Sent an E-mail to Ames and they replied immediately and told me to send them back and they would send me a new pair. Plain and simple. I had one other issue with a set of date coded wires, I called and was pretty hot over the issue. Steve Ames called me back and made things right. I'm not so sure the others would be so quick and willing to make things right. I've had issues with CI and they were not willing to help, had an issue with NPD and they were so so.