You are extrapolating radioactive energy release per radioactive decay event.
"Have the results you're speculating about ever been observed at all under any conditions?"
Exactly why you can't make that extrapolation...
Indeed. I agree that there is some degree of "extrapolation" (and interpolation) involved because the energy release of every instance of a decay event was not observed and measured. No physical constant based on measurement of a physical event or property ever has been.