Heating reduces psylocin apparently to a different indole, thus making your product approx., like what, 15% or so less depending on the shrooms? (Could be wrong %-wise, no flames). Psilocybin OTHO would remain straight, so the bulk majority of active material would be okay to simmer some, wouldn't apply any serious heat, although I guess this is okay as well. I think the seeming increase in potency is the fact that the shrooms are completely broken down and more of the active psilocybin is released and it hits the body faster and sooner. Kind of like how I believe crushed pressies fuck you up more than just swallowing a pill whole (x I'm talking about of course).
As to heating the pure active compound ...why? This seems like if there were a chance for psilocybin to get fucked up by heat, it would increase in an environment free of the fungal body. Then again, maybe not if you're completely grinding up dry shroomies anyways. Try it and find out, just don't over do it with heat, only what's necessary. Test small first of course.
We need new drugs.