Chris, that's a fair point, and I overstated it. A job that checkpoints, runs to its limit and resubmits has done useful work, so counting all of its energy as waste is wrong. The tool reports energy "at stake" rather than energy saved partly for this reason, but saying the job "returns nothing" went too far.
I think the two cases can be told apart from accounting data alone. A checkpoint-restart chain usually looks like the same user resubmitting a near-identical job shortly after the timeout, and a genuine failure usually doesn't. I'll add that split, so the report shows TIMEOUT energy both with and without likely restart chains instead of a single number.
If you have a rough idea of what fraction of timeouts at your site are intentional, that would help me calibrate it.
Thanks for the correction.
Jim