What is really needed is a range of Temilaq paints to find out exactly what temps the AMP unit does goto. I have a feeling that they may reduce the peak temperature reached now, as in units with the Aztec. My guess is that there is a light sensor in close proximity to the case. so when the case starts to glow it is picked up by the sensor and a data point is obtained from that. Note AMP now say a sacrificial case is needed. So they must be over heating it. How to tell either temp or colour. So from that fail data point they then back off a certain amount so that they no longer produce any light. I use the 750 and there is a little bit of room between that temp and starting to change colour, of course this time between those two points is based on the rate of temperature change and why IMO think slower (just a little) is better.