The concept behind the "auto light adjustment" (Voyage only, I think) suggests that in the darkness, you use a very low light setting. This helps avoid eye strain, etc.
Have you tried a lower setting (5 or so) rather than your 19? I admit I only recently turned the auto-adjust back on, but I liked it while recently reading in the complete dark (in a trailer; conserving the battery lights).
Perhaps not, but you *might* like it lower if you tried.
