I think that the Catholic position is that we are learning, *deepening* our understanding of the deposit of faith, for the promise is that the Spirit will "guide you into all truth" (John 16:13). Previously I think you mentioned that doctrine does not change, but it does evolve. We agree. Doctrine *develops* organically, such that we always retain the deposit of faith while our understanding of it is constantly deepening. In that way there is more, and yet there is not more. There is change, and yet there is not change. That is the nature of organic growth.
-A8
Individually, we do grow, I would agree. Doctrines do develop, but it is, as you say, 'deeper' rather than new knowledge; deeper understanding of the same belief, of the same teaching; change without change (I like the way you ut it).
A true Church can only 'discover' more of what it already knows.
The process of deepening our faith will continue, no doubt, in the life to come, indefinitely, for God is infinite and eternal.