500 lumens for 3.5 hours on 1x18650, optimistic? Lumapower Signature Tactical VX

lumapower list the Signature Tactical VX sst-50 as having 500 lumens output for 210 minutes on a single 18650, surely this cant be right can it?
i know manufacturers exaggerate the runtimes a bit but this sounds way too high.

http://www.ledfiretorches.co.uk/lumapower-signature-tactical-vx.html
http://www.illuminationgear.com/SIDEBYSIDE27729.html

It is all the difference between linear regulation and flat regulation.

I think palimpsest is right. Take a look at the thread with the output curve for the MG p-rocket SST.
http://candlepowerforums.com/vb/showthread.php?t=292484&highlight=p-rocket&page=2 See post #31 for a graph.
Output drops dramatically from time zero. It is semi regulated, not a flat output curve which you would get with a fully regulated light. So, output could drop quickly and there's no guarantee that they're making runtime to 50% of output either. I would like to see someone do a review and show the actual output graph on high. Manufacturers like to make inflated claims!

Without even seeing this light, I unfortunately have to assume that the 500 lumen figure represents the inital burst brightness, after which the output will fall steadily. If you take a look at some of the other offerings from Lumapower (Incendio V3, Trust series, D-Mini) you can see that for the most part (I cant speak for all their lights, just the ones I've personally seen runtime graphs of) Lumapower lights can described as semi-regulated at best. This is what kept me from buying both the Incendio V3 and the Trust 1. If they were even close to full regulation at their advertised outputs, they would be game changers. (350 lumens regulated from a 123 sized EDC? Where do I sign?:twothumbs)

Well, I have V3 and compared to Mini CR2 (CW) on RCR2 it produces less amount of light, as I could judge by wall and ceiling tests. With RCR123 - a little bit more.