Dear Resplen,
My understanding is that higher levels in Reiki makes us a clearer and more open channel...not changing the nature of the energy itself. I suspect also, that Reiki may not respond to the same laws of electromagnetic energy, as it very well be something very different in nature.
I've heard other forms of Reiki, such as Karuna, claim to be higher frequency, but I'm kind of dubious of that.
Incidently, a while back, Bruce posted something on the claims of higher frequency being automatically assumed to be better. It was a very thought provoking point of view.
Blessings,
Roxy