I am pretty sure I was getting ready to end the run right at 40 seconds and the beam moved off of the sensor a bit. I ran it for a full minute before that run and it did not seem to taper off sharply for me. Only the 1-2 mw per few seconds. I am sure at some point it will taper off sharply I do not know where that is or what the limiting factor would be to cause it. I can tell you that the diode is sinked very well and right after the 1 minute run I was feeling all over it to see if the material was heated up at all and as far as I could detect it was barely warmer than the room temp.
At the risk of sounding sacrilegious, I wonder how it would do with a 1.62W driver? Seems like that might buy you some diode life and still have you over 2.2w or so? I swore I had done all the buying I needed to do for now, but this makes me very hungry.