Hhmm, maybe I'm not remembering clearly, but:
Here 495 kcd at 6.5 amps
Here's a couple in the list, close to 500 kcd. I just recall rdrfronty, or ILIKEFLASHLIGHTS seeing/testing over 500 kcd for a TN31vn and I was frustrated I couldn't match that. I think rdrfronty re-tested against mine and found he initially tested high and dropped it lower in his lists and postings.
We talk'n some classic BLF modding history here... 
Those modded TN31's got pretty hot even at relatively low amps - there were like no fins and very thin around the hot zone by the LED.
OK - think I thought the high mark was 600 kcd, and most of us were in the 500's, but I was off by a 100 kcd: 500 kcd was the high mark, and 400's was typical.
300's? Not sure but could be an issue with the LED, dedoming process, basic light like the reflector, etc. or maybe over amped. I modded one that I found kapton tape on the bottom of the MCPCB! Factory mistake, leaving a heat barrier in one of the most critical spots of all - mine wasn't the only one reported like that.