You are welcome.
It is amazing what you can do with these little gadgets, especially for datalogging. A simple hobo type datalogger with one channel can run you $200, but with a couple of IC’s and a little perseverance you can do far more for next to nothing.
I pesonally feel that the firmware is not waiting until the ADC has completed it’s conversion before reading out the values.
I believe that is a good assessment. When I get time I am going to experiment with FOR lops and see if I can come up with a definitive delay time. In my app I have the luxury of not needing a recording for 5 seconds so did not try to optimize the timing.
btw,
the occasional peaks, I got turned out to be very closely correlated to me moving my cordless mouse … 
Hi Lars, if you have not solved your issue yet, please check out > https://www.pyrosales.com.au/blog/cat/thermocouple/post/making-sense-of-sensors-part-5-type-j which may be able to provide you and/or other members of the community more information about type J thermocouples.
I can also ask the owner of Pyrosales any questions that you may have to?