Adam is right on (as he should be with his particular level of experience). The main idea is that the ambient themperature is where it needs to be with basking area, and less of where the heat source is. Temp is temp, sure the physics of the different types of heat radiation will dictate how a particular temperature is reached but in the end 92F is still 92F when dealing with reptile heat sources. Of course someone could argue that sticking a microwave emitter on top of the cage will reach 92F but will in turn kill any living thing, but lets be realistic when it comes to overhead, under the tank, space heaters, back heat, or whatever the important thing is that a snake can regulate its body temperature by moving arround within its habitat.