Thought id help here since I was in the service industry for some time, including service advisor a while back...
The issue with NPF or No Problem Found, is typically dealerships/manufacturers only offer .2 to .3 hours of time for diagnostic on most of these issues, IF any at all. That means the tech has about 12-15 minutes to grab your vehicle from the lot, diagnose the issue etc and park it again before he's "losing money". I don't agree with this practice, and typically until you complain to the management or Chrysler about the issue, they aren't given any extra time. As a mechanic, I didnt care and was more of a figure it out until its fixed type, but most mechanics put their "I drove it from the lot, back to the lot and found nothing, give me my .2 diag time". Once you complain, typically management will give them an hour or so of pay to look into it further.
As far as TSBs and warranty repairs, often its considered warranty fraud for the dealers to just replace parts because someone wants them replaced, and a TSB isn't a recall, so its not required they do the repair unless necessary. Therefore, if you read the TSB, and it says "If the customer makes this complaint, you replace XYZ parts", you need to make sure your complaint matches what it says when you go in. If they are dicks after that, then there isn't much you can do except complain some more, but most dealers would gladly take the warranty work, especially if they are slow, unless Chrysler is doing random inspections on the parts and theres a chance they could get charged back on a non faulty part. When I was at Ford, the Diesels had TSBs released on a seemingly hourly basis, so just about every diesel tech said "make sure they complain about this and that" so they could get the repair time while in there to replace turbos, injectors, and whatever else, so when Ford caught on and started denying dealer claims for repair, that quickly came to an end when the dealers had to fork out $700 for a turbo and $300 for each injector they replaced just because they wanted to.
Im absolutely dreading taking my truck in for service if I ever have to because I remember the games all too much that the techs would play, but as a tech, I remember the games the service advisors played trying to get things done for free or less, or pre-diagnosing something etc. Sadly I end up repairing things myself unless theres a significant parts cost, then it goes in. BMW was giving me hell a couple months ago for warped rotors/glazed and grooved pads on my X5 when I had a maintenance plan that covered brakes, warranty, and known TSBs for rotors warping due to the weight of the SUV, but they denied my claims all the way up to the top, so I just sanded the pads down on my own to make the issue go away. Sadly thats what things have come to when they have the upper hand and all we can do is complain, or throw money away with a lawsuit that gets you nowhere.