Yup, you've got that all correct. I started referencing the knob position in more ambiguous terms due to the direction change.
25% intensity is the halfway point (arrow pointing straight down)
50% intensity is 1/4 of a turn toward the max intensity
100% is then most obviously the max intensity
Note that while most would consider the knob at 3/4 of max meaning 75%, this is indeed not the case (it's not perfectly linear). It's very important to note that you double the intensity from the halfway position to the 3/4 position, then double it again to the max level. It's easy to hit the screen with way too much light if crank the intensity up without it being mature enough to handle that intensity.
Also note that the maximum intensity of similar size off-the-shelf fixtures matches up with the 25% level of these fixtures. In short, these lights are at least double if not 4x as intense as most