Hello,
answering your questions.
What is the serial number of your USB-2416?
A: It's 1F5C19B
What type of thermocouple are you using?
A: I've been using type K
Did you allow the USB-2416 the recommended 45 minute warm up time?
A; Yes, it has been warming up for more than 45 minutes
What are you using as a standard, that is telling you the USB-2416 is 8 degrees (C or F?) out of tolerance?
A: The standard used is a Fluke 5522A, in C degrees
Going forward until this issue is resolved, with regard to software please just use InstaCal and its built in tests.
Regarding the USB-2416 settings (as found in InstaCal). For each channel you have configured for Thermocouple, what is the data rate you have selected? The recommended data rate setting
A: I tried with the rate that you suggested it, and with different rate too.