I just gave attempting to sear at the end of the cooking session a try, but it turned out unsuccessful for me. This was from more of a practical standpoint related to my burn, since near the end of the burn my coals were burned down and the sear wasn't at sufficiently high enough heat - like the short sear I had found to be very successful at the beginning of the cooking session. The late sear attempt was with only a dozen drumsticks, but the skin was rubbery and while the taste was nice and smoky there really wasn't any more smokiness to the flavor than we have experienced using the short sear at the beginning - at least any difference that we could taste. I use wood and charcoal and always get very smoky flavor - and maybe it's hard to tell the difference between very smoky and super smoky.
Having said this I do get the theory that was pointed out, and appreciate that it represented an opportunity for improvement, and I am just reporting the practical nature of the heat (BTUs) available during the burn for effectively searing.
In my case, I am using an offset box horizontal smoker/grill - that has a 40" long X 20" deep cooking chamber. The last 10" of the cooking chamber nearest the firebox chamber is hot enough to grill and sear food at the start of a long burn, though apparently not at the end of a long burn (without adding a bunch more wood/lump fuel to the firebox which is sort of a waste of BTUs at that point, being very near the end of the burn). I can smoke food very successfully by spreading it over the remaining 30" of the cooking chamber - not using the 10" nearest the firebox chamber. I will often cook (grill) a dinner of steaks/chops at the hot end of the cooking chamber, and then continue to use the same burn to also smoke a batch of poultry parts for packaging subsequent meals in tupperware. The methodology I use has been derived from practical experience and a desire for efficiency (use the burn for multiple meals, while efficently using fuel). It's a compromise approach from a theoretical standpoint, but the results are excellent from a practical standpoint.
In summary, the short 5 minute per side sear at the beginning works best overall FOR ME, with my equipment, and my efficiency goals. It may not work for others based on your equipment and goals. There are clearly many successful methods out there!