I still think that the reason he told him the name of the attack was because he realized how to shoot it off his own free will, not because he became more powerful... And that by him telling him his name, and Ichigo knowing the name, the attack would become more powerful...

Remember that Getsuga Tenshou is an attack that absorbs Ichigo's energy, so knowing the name of the attack will increase Ichigo's energy, hence making the attack more powerful...

I mean, when Ichigo learned his soul slayer's name, it wasn't because he became more powerful, by learning its name he became more powerful... So, I think the same system applies here...

If becoming powerful is the requirement to learn stuff from the soul slayer, then Zaraki wouldn't have any trouble learning more from his.. but as we have seen, the deciding factor is something else...