OK, let's see if I can describe this properly.
First, the machine had a full treatment of Ablaze Ghostbuster LEDs. They have additional circuitry in them to prevent them from turning on in low current and/or short pulse conditions. This also causes them to not turn on when set to low brightness settings with LED OCD. It's the same with CT Premium bulbs.
When we first added the OCD board, and turned the machine on, attract mode was not very impressive. By default, the bulbs are set for the following brightness ramp:
10 20 30 40 50 60 70 85
Testing them using the manual test method described on the LED OCD webpage, however showed that the lamps did not turn on at all until about 22%, and were flickery up to about 40%. This caused the default settings to be rough and flickery since the low end brightness values did not work well with the GB LEDs. I changed the ramp to:
40 46 52 59 65 72 78 85
This was much better, but a bit dim, so I increased the top end of the brightness ramp making it:
40 48 57 65 74 82 91 100
Short of a few bulbs that could still be brighter, attract mode now looked pretty good. Remember these were Ablaze GB, and brightness is really not their strong point.
Once we started lighting the Villain inserts, there was still some mild flicker. I needed to find out which output brightness levels were being used for each of the Villain mode levels. With Green Goblin at level 1, I checked the Advanced checkbox in the configuration software and changed the LED OCD ramp to:
100 0 0 0 0 0 0 0
Since this didn't light at all, I knew B1 was not being used at all at level 1. Changed to:
0 100 0 0 0 0 0 0
This caused the lamp to flicker, so B2 *is* being used at level 1. I continued this process to map which output levels were used at level 1. We advanced GG to level 2, repeated the process, ... Finally, we had the following mapping:
Villain Level 0 - Off
Villain Level 1 - B2 & B3
Villain Level 2 - B5 & B6
Villain Level 3 - B8
In order to have a dimly lit Villain insert be steady, the B2/B3 pair needed to set to the same value, as well as the B5/B6 pair. I changed the ramp to:
40 48 48 60 75 75 90 100
The flicker in the Villain inserts was gone, but you really couldn't tell a difference between a dimly lit (Level 1) and fully lit (Level 3) insert. I played with it some, but there wasn't much I could do. The low end being limited to a minimum of 40% really limited what I was able to do. This same ramp turned out to be appropriate to avoid strobing on the 2X bonus white arrow insert.
We also put a couple of Ablaze 3-LED bulbs in Green Goblin and Doc Ock, and I was able to reduce the low end to 10% without flicker. This allowed me more flexibility in separating the brightness of each mode level, but you'd still be hard pressed to tell between Level 2 and Level 3.
LED OCD can be used to eliminate the flicker caused by progressive dimming with LEDs.
The process to fully configure it can be a bit involved, but once a game it figured out, applying it to different bulbs is trivial.
The progressive dimming effect, even when it's not flickering, is not terribly useful.