In article , DKat
says...

Again you are talking Temperature vs Heat work. They are critically
different. I don't know how else to say it other than they are correlated
but not the same.

In simple terms: imagine a plot of temperature against time for the
firing cycle. Now draw a line across at the minimum temperature that
the glaze will flow. The relevant heat work is the /area/ under the
curve but above that line, and is dependent on both temperature and
time.
Cones reflect this because they sag faster at higher temperatures, and
sag more with time at any particular temperature above their
characteristic minimum temperature.