Well, in this case i don´t agree with our Tactic-Yoda. To say it clear, he makes all the maths, statistics and number-things, i just look at my players, how they perform, and which effects newly added players have. My opinion: SB works not with only 1 guy, there is help-defense. In U21, we had a game where the PF made a new SB-record, but he was far away from beeing the best shot blocker in the team. Now it´s the question, what this means for your team: For me, a SF shall have at least 10 SB. With PF and C really strong at SB (15+), ur SF will benefit (and i´m interested how this´ll work with 2-3 zone, i´ll see it next season).
So if u have strong shot blockers on PF/C, i´d give him SB training, the better the best. If ur PF and C suck at shot blocking, let it be. Here the words of Yoda are totally correct :)
But as i said, i play with stomach, the other one with brain. Maybe my thoughts are totally wrong, and there just had been lots of coincidences the past season games i looked at.