i know that many people asked something similar but it's just to be sure...

I completed the Game on true ending and want to farm every and master every blood code. I noticed that the easiest way of mastering high tier blood codes is the final stage "tower of the seal" (plz don't wonder if the name is not correct -> i quickly translated). And as almost anyone noticed we're not allowed to take the the ties that binds from "saving Lou" to the main game (but were allowed to claim the last blood code from the recurgance core).


Now my question is:
Is it somehow possible to level up S-Rank blood codes in "saving Lou" and transfer the masteries to the main game or am I forced to farm the "tower of the seal" to master them?