Isn’t it amazing how people can get so confused about something as simple as summer decandling!
I once attended a class on Japanese Black Pine conduced by Warren Hill. It was held in mid-to-late October. He taught to have everyone decandle their JBP then, in mid-October! He said it was the “normal time” to do it! I couldn’t believe what I was hearing! (I actually took the class because I had been told that Warren was teaching that. I didn’t believe it. So, I took the class. And, it was true! He WAS teaching to decandle in October!)
There is a RARELY USED technique to force backbudding on JBP by decandling in the fall. It is a “last, desperate, if this doesn’t work throw the tree away” type of technique! And that is to decandle in the fall like Warren described. The tree won’t have time to produce new shoots before winter. If you’re lucky, it may produce backbuds at the old internodes. And they may, or may not start growing next spring. If they do, it worked. BUT, you can’t decandle them that year. You have to wait a whole another year before you can decandle. Oh, and if you do the fall decandling, don’t pull any needles. The tree needs every thing it’s got to keep living.
I’ve never had to try the fall decandling, but I saw the effects on the trees in that workshop. It nearly killed those trees. One person nearly lost a very nice tree, it took 3 years for her tree to recover!
Don’t do it!
Oh... soon after that workshop, Warren suffered his devastating stroke.

In speaking with some of his long time friends, they had noticed that over the previous few years, his memory had been faltering. I suspect he had suffered some minor strokes that caused his memories to get scrambled, much as my mother’s did after her mini-strokes.