I am researching trane units and have a warranty question. Their website states the units carry a 5 year basic warranty. It then seems to imply if you register your warranty online or by phone it gives you an additional 5 years if it's for your primary residence and you are the original purchaser. Am I reading that correctly that my registering online or by phone gives me a 10 year warranty? I spoke to a dealer but they were not clear on that point. Also if I purchase a new trane will other people working on my unit be able to pull up warranty info by looking at the serial numbers on my unit?