The same pattern for me Mike regarding Scan and my 1999 model 95DU. Enjoyed for the first couple years then one thing after another. It is in my garage in the Coleman cooler I mailed it in completely refurbished, including upgraded circut board. They said I should be able to use it or sell it which ever I choose. When the unit became more problematic, I started sending it to them per their reccomendation so nothing would be missed as they have testing equipment I don't have access to. If I remember correctly one such testing device would be precise exhaust/combustion measurement, which I would think be tied to calibration decisions.
Rather than see if the refurbished 95 would be more reliable or risk repeating what I have been through, I decided to stay with the Wallas brand and upgrade to the 85 a few years ago for several reasons. 1) efficiency of the fuel to weight/space factors 2) convenience of a combo. heater/cooker and 3) because I was told by Scan they are more robust in some ways, and less prone to the failures of the 95. We will see and the results asso. with my 85 will determine whether I will continue with Wallas.
I was told my newer model 85 gives them access to how many hours are on it when they test it on their equipment so it helps them with service decisions. I also need to be able to know when to service the unit since they have made it clear, if you want more reliability, treat the unit like you would any machine that needs routine maintenance, like your tow vehicle. So as some others have suggested on this site I installed my own hour meter so I have the opportunity to follow their servicing recommendations, and for me some way to monitor what is happening over time. I bought my hour meter through Napa and was instructed by Scan how to connect it.
My brother lives in Alaska within the Upik Eskimo culture. Years ago he told me a story I can identify with now as I apply it to my Wallas. I don't remember exactly how he told it but it went something like this. Someone would tell the elder eskimo this is what is best, and the old man would respond, "we will see".
I am hoping the hour meter will help me to more objectively do that.
Tom