There is a ton of information on this site that I read through prior to committing to painting my own car. Below is the page related to paint technology and summerizes the differences between the primers and sealers, 1k vs 2k, etch vs epoxy, etc...
http://autobodystore.com/ms7.shtml
I should have mentioned in my earlier post that I used a sealer over the K38 specifically bacause the P-sheet says a sealer MUST be used if Black base coat is to be applied over the K38. I dont believe the k36 sheet says that so I guess it does not apply there. As marco pointed out the K38 was the only thing I allowed to sit while doing body work since it has no recoat window. The K38 was shot the day after epoxy, body work was completed, and then the NCS sealer, BC/CC were shot in sequence wet-on-wet.