I hesitated replying to this as I am by no means a thermoplastic expert but here is what I think.
I understand that the glass point for common ABS filament is around 105°C but it does vary significantly among manufacturers depending on the blend of A, B, and S

ABS does not warp at a specific temperature. If you uniformly heated an ABS part and then allowed it to cool slowly and uniformly, it would not warp. ABS does, however, shrink when cooled... as much as 1-3%. The problem we face with our printing results from adding a hot layer onto already cooled layers. As the hot layer cools and shrinks it pulls on the layers below it, tending to pull them up and in. This results in the warping and pulling up from the build plate. Because we used a HBP, the first few layers are kept warmer so the shrinking/warping tends to occur a little higher up in the model.

There is no secret in how to prevent this, but more an inability for hobby type printers to manage this effectively. Stratasys along with all their closed patents for managing the chamber/model temperatures while extruding has no problem with warping. The key is to keep the entire model at a high temperature somewhere below the glass point. I believe the optimum chamber temperature is around 80°C.
In our machines, this is not easy. The mechanics of the extruder, the yet to be extruded filament cannot be kept at this high a temperature if we expect them to continue to function for long.

I believe that we can obtain satisfactory results in minimize negative impact on our extruders if we keep the chamber enclosed and get the temperature up to around 50°C. We also must eliminate all drafts e.g. the fans exhausting hot air and drawing in cold air and the extra nozzle cooling fans that some have added to extruders for PLA, etc.

Now back to the Dreamer... If the chamber temperature is 50°C, but the main board is 30°C, there will be a 20°C error in the measured and displayed temperatures assuming that the extruder wiring board is also at 50°C. BUT a 50°C chamber temperature will also reduce the cooling of the cold end, the stepper motors, etc., so it is likely that we will still see increasing temperatures (and error) in that critical area and still some tendency to runaway. My other concern is that I don't believe the plastic case and ABS parts will last long if they are constantly exposed to 50°C plus temperatures.

I see the thermocouple fix as critical for any attempt at higher temperatures. Once that is done, I think that we cautiously increase chamber and extruding temperatures and test where the upper limits are. Without the thermocouple fix, we have no real idea what the temperatures really are at the extruder other than to be sure they are higher than the displayed value.

I print a lot of ABS and as long as my ambient temperature is around 30°C and I keep the doors closed an eliminate drafts, I have had reasonable results. I've only had to scrap one model due to warping and that was when I tried to print a 4" x 6" thin walled box with an ambient temperature close to 16°C
I have already meted my first X carriage so I know it is easy enough to get extruder temperatures too high with the current software.
Graham