You can do the calculation for good approximation. I have a 325 clicky and lightbox and did the calculation once and compared it to my metered results. I found the two to be close enough for government work, certainly closer than than the naked eye can distinguish, and much better than most Chinese-brand lumens I've tested.
If you look at the manual, under the section "internal brightness levels," you'll see that Henry strives for dead linear increments between each level, or ~ 1.5x depending upon starting and ending output. In the case of my 325, a ~1.525x increment works out, or 0.02 lms x 1.525^23 = 328 lms. In other words, 0.02 lms x 1.525 = 0.0305 lms (level 2) x 1.525 = 0.04651 lms (level 3) x 1.525.... etc, etc.
So assuming Henry is applying the same approach to the 12 level tactical, and you also have a 0.02 min and 325 max, a ~2.415x linear increment works out or 0.02 lms x 2.415^11 = 326. In other words, 0.02 x 2.415 = 0.048 lms (level 2) x 2.415 = 0.1166 lms (level 3) x 2.415 ..... etc, etc.