excess heat ~ runtime
leakage from atmosphere ~ runtime
The meaning is a little unclear to me. I think you are saying that both excess heat and leakage increase with time, so they will both go up in a correlated way.
Are you confusing power (that is, heat) with energy? In most cases shown by Miles, excess heat does not increase with time. It varies within a range, but you do not get more with more time. See the graphs at the end of this paper:
Net excess energy, when present, does increase over time, of course. Both the power and the energy from electrolysis have no effect on the helium level.
Miles does not measure helium during electrolysis, but helium must increase over time, because it does not leak. After a test, the same amount of helium is found in the collection flask when it is measured repeatedly, several times, months apart, so we know it is not leaking in or out. Helium also increases monotonically in experiments where people measure it on-line during electrolysis. It increases faster when there is more excess heat.
With Miles, the duration of the helium measurement was always the same, 1.2 hours. So if helium was leaking in at a constant rate, there would be the same amount in every sample. It would not correlate with excess heat. If it was leaking in at random rates, it would not correlate with excess heat or anything else.
A small amount of helium does leak in at a constant rate. The background helium. It is the same for all 1.2 hour samples: 3.4 to 4.6 ppb, with no excess heat. With excess heat it was 7 to 9 ppb, correlated with the level of excess heat. If this was a leak, it would be somewhere around 1,000 to 5,400 ppb (atmospheric). In some experiments, they start out at 5,400 and go up from there, which eliminates the leak hypothesis.
runtime - depends on excess heat. e.g. if no excess heat some protocols will terminate the experiment early (F&P have done this).
Runtime is always 1.2 hours, as I said. With other on-line experiments, runtime for helium is the entire experiment, including times when it produces excess heat, and times when it does not. But excess helium above background only appears when there is heat, and the amount is correlated with the heat. When there is no excess heat, neither excess heat nor excess energy for the entire experiment increase at all. They are both zero, and there is never any excess helium in these cases. Nothing above background.
I discussed these issues here: