I appreciate articles like this one as well - the ones that kind of focus in on experimenting and evaluating various process/ingredient aspects in an unbiased way. In particular, I find it interesting to look at these decisions on process at a "homebrew" scale...... when often, commercial scale is compared to homebrew scale - which may, or may not hold up.
In regard to decoction, I brew a variety of german lagers (Helles, Dortmunder, Pilsner, Oktoberfest) on a pretty regular basis. I have tried various decoction methods, various infusion mashes, etc. And, for me, I have sort of settled in on a direct fired, recirculating step mash. This seems to give me the clearest, cleanest beer, with a good malt profile.
Generally, I mash in to an initial temp that settles right around 128-130. I only let it sit at this point for 5 minutes or so, and I turn on the flame under my mash tun and start to recirculate (No pumps, just manually opening the spigot and draining into a small stainless pot and pouring gently over the grain bed.)From the time of dough in, until my mash reaches 145-149 range is probably 15 minutes, 20 tops....... So, I am spending a pretty short time in the 130 range. I leave it in the 145-149 range for about 30 minutes and then turn the flame on, recirculate and take it up into the 154-156 range for about 20-30 minutes. Then recirculate and sparge in the 165-167 range to collect wort.
I think the direct firing of the mash as well as direct fire on the boil kettle as wort collects provides some caramelization/melanoiden flavors. However, the main thing I have noticed with the step mash is that I tend to get clearer beer than I do with the infusion mash. Any flavor differences are probably minimal if I am being honest. However, I really was hit and miss with hazy/cloudy beers when going straight infusion. The quick step mash seems (at least so far) to give me absolutely brilliantly clear beer.
I have also played around with boiling the first runnings of oktoberfests (maybe a half gallon or so) for about 10 minutes in the boil kettle before proceeding with the sparge as a way of attaining that "melanoiden" type flavor/profile. I can't say, definitively, that it made a difference..... it was good, but, was it better?
In my experience, I will say that I have found no evidence or trend that would ever want to make be repeat doing double or triple decoction type mashes - as I just have not experienced any real benefit from them. I like the step mash for sure in regard to clarity and fermentability of my wort. I am still playing around with quick single decoctions toward the end of the mash, or boiling down early runnings a bit to accentuate some of those flavors. My opinion on these, from my experience, is still out.