u/Cheap-Abbreviations5

This is basically a question looking for where I can find a rule that I seem to be missing in all of the books I've got my hands on. I'm getting geared up for a Shadowrun game starting in about a month and I haven't played Shadowrun in a while, so I figured I'd use some of the character creator tools to help smooth out the process. Character I'm working on is a Physical Adept. One thing I've noticed is that most of the character creators (particularly Commlink6, which I'm using in this case) seem to have an option to allow characters to spend Karma to purchase additional Metamagics/Submersions/etc. I like this, because it lets me spend a bunch of my Karma on extra Power Points to spread out my options for Adept Powers, but I'm having a hard time figuring out where this option is present in any of the books, or where the formula for the cost is coming from. I've got several of the books, including the core rules Berlin edition, Sixth world companion, and Street Wyrd, but I'm not finding it in any of these, but maybe I'm just missing the page/passage that specifies it. Anyone able to help me out?