Steve, thanks for the site, I'm going to have to take a look at it.
Zevon8, we are using a rather expensive (it looks expensive anyways) datalogger to measure the data. It has screw terminals for the thermocouples, then you specify in the software as to which type you are using. So I figure that this might not be the cause of the error.
Although there are 3 terminals for each channel, maybe the type k uses the bottom and middle, and the type t would use the top and middle.
Thanks for the suggestions