question about vc

Yes, after you hit 30 you will receive full value of non bundled games and 20% of bundled games.

you'll receive the value of the non-b game PLUS up to 20% of the game value depending on the value of the bundled games that exceeds the value you already received

No. That 30 is actually 25+20%: the main rule is that your CV from bundled games can not exceed the 20% of your CV from non-bundled games. However as an incentive, the first 25 bundled CV points are counted as non-bundled.
Putting aside this 25-point twitch you can say CV = min ( CVnonbundled+CVbundled, CVnonbundled*1.2 )

If you understood it, it would not be magic.