So I know you can go to NikonUSA.com and register your lens, which is what I did, however, I also notice that with the lens are both a postcard that says you need to complete and send in within 10 days. Along with this is another little sheet packet that says you must fill out and send in with proof-of- purchase. So my question is, if I register the lens online, is that all I have to do in order to get the 4 years extended service coverage? Or do I need to send in the post card as well as registering online. Thanks in advance.