quite true, temp is definitley not the only variable that matters, I'm using a timed power step down approach to control the others and it seems to work quite nicely.

I was going to chime in like mkane. I've found there isn't one end-all-be-all parameter for roasting. It is a dance of many variables within a window of values that defines a good roast. A long roast to the same drop temp as a short roast will be more developed/darker, for example.