If you are running the engine as no nitrous but all motor, the high gear retard can definetly help.
When I developed that thing it was all analog using chips but it was not originally a nitrous retard. It was for the capabillity of keeping the engine at an ignition timing it was confortable with while pulling in high gear but allowed the car to be over advanced for launching in lower gers to give more low gear bottom end power. That probably doesn't make any sense of how running in an overadvanced condition can add power on the low end of the track but it does.
The basic concept of what we did was not begun by me. Old Stock Class racers using Point type Ignitions were using dual points and grounding out one set of points when they hit high gear with a remote switch in the car. WE just took their idea and ran with it to make it work with the MSD by using resistor chips to control the amount of resistance we were using to shunt to ground and that ended up taking the multiple trigger signals in the box and slowing down the amount of time in miliseconds it took for the triggers to reach the capacitors which we was using for stepping up the voltage like an additional power supply. Kind of like a car stereo amplifier does. That is how we got 12 volts to be high voltage.
Anyway. Yes' It can work very well and can increase your ET. That means helping it. You can also use the retard on a slick track with a remote switch. That was also a part of the original design.
Steve Masters took my original old fashioned old school Start/Run Retard that had been integrated into several of the different add on retards and made it better and made it to be Digital using transistors and included it into his Digital Boxes that almost everyone now is using.
When Steve first developed the Digital 6 it had far more energy output capality than was ever anticipated. It was better than the Pro Stock racing only MSD7AL2 that cost twice as much. Ouh oh. So that led to redevelopment and hopping up of the 7 series to give it even more energy which came out in the MSD 7AL3 boxes. Soon after the combination of what was sucessful in the Digital 6 was mated with the additional energy concept into the king of the ignition boxes, the Digital 7.
I have never been an employee with MSD so don't get the wrong idea. I just had some ideeas that MSD's Raul Konch (Moved on), Russel Stevens (Current National Sales Manager), Jeff Gaul (Deceased last year), and Joe Pando (Current Liason to NHRA-IHRA) worked out together by telephone and the mails, to end up with the finished product which Warren and I tested first protypes of. That was way back in the very early 1980's.
In a way my asociation then with MSD is kInd of like my piston ideas and designs that my piston company BRC Performance is making now for me. There are many products that I have gotten the mfg to altar for my desires, but I am by far not the only one they do this for. It is just recently that I was given any public credit for having any part in anything special in the industry. No money has ever come to me for anything. I just get stuff done the way I want it. Just like getting a cam cut to my specs. If you design your own workable cam profiles and pay for it to be made you can get it made. Comp Cams is now selling one I had them do for me several years ago. I don't always design my own. At times I use things already available depending on the budget.
You will enjoy the benefits of any the new Digital Boxes. Use the HVC Coil for the box and use a noise filter to protect the box. I strongly suggest using only the MSD 8.5 mm Plug wires too. The Digital 7 box will melt the end of the conductor of the best Holley Anihlator Plug Wires. Ask how I know. lol.
For a really strong MSD Box the MSD 10 is king and it is huge.