Well, I give up. Finally ceased the test...the light ran for 28 hours on low AFTER I'd run the batteries to well below regulation. At the time I stopped it, the measured output was around .15 lumen - batteries had 1.52 and 1.67 volts left.
Let's think about this - Scout ran his for 53 hours on low. I ran mine on high for 2 hours 10 minutes, then another 28 hours (and it will still light the emitter.) If Scout used his on low for 15 minutes a day, that's 212 days. If I ran mine 15 minutes a day combined, that's almost 9 days on high plus 112 more days on low.
.15 lumen not useful? Really? I invite you to enter a dark room with night adjusted vision and fire up a 1/10 lumen light. Those of you who know will agree, it's incredibly useful - almost 'too bright.' And it was only in the last few hours that it dropped below 1 lumen. At the beginning of the low "let's exhaust it" test, the light was at 3 lumen and would still switch to high with a burst of around 50 lumen. Only after around 20 hours did it begin to drop below 3 lumen...
Now this isn't meant to morph into a comparison of run times and who's light does better, etc., but rather to tip our hats to a pretty awesome combo - the Malkoff light module and the Elzetta host - combined they offer great output, bullet proof construction, and AWESOME run time on primaries! I'm like scout - I don't typically use primaries, but in these lights I just might decide otherwise when I want to ensure I have light for the long haul. SHTF? I'm grabbin' an Elzetta with primaries! Oh, and BTW, I've added an M61, high CRI M61, M60F and M61NLL to my stable of light modules. Oh, for enough hosts to run them all, but Elzetta gives you that option!