Sounds reasonable. I do that with JWP in the spring.As I remember his reasoning for withholding fertilizer until after hardening off was to prevent the new growth from extending a lot so you'll get shorter internodes and keeping the needles from lengthening.
Decandling is pretty stressful on JBP. Once you get a lot of ramification, when you decandle, that generates a lot of new shoots, which uses a lot of resources.
There’s lots of variations of the details of JBP cultivation.
Even within Japan, there are many approaches. Ryan is doing things the way Kimura does. Boon does things the way Kamiya did. They’re similiar, but slightly different.
Remember, bonsai is quite competitive in Japan. Each Master has his own methods he thinks gives him a competitive advantage over his peers. Do they share their secrets? Even with their apprentices? (Who will eventually become competitors!). Maybe... Maybe not...