Bsk: P16108 board services as an "analog board" (A/D) and has a group of t/c inputs that can only be tuned as a group (pick one to tune and that calibration stands across the board).
One of the heater zones took a hit and now it seems to operate on a different slope from the rest. ie. the higher the temp the further the spread from actual.
The cost to replace the entire board is a bit ridiculous, perhaps incentive to move on to a better technology? Definitely incentive to seek someone who can make the repair.