This is basically correct but i would add sometimes it's better to add chips than to add mult. For example, if your score is something like:
10 x 50 = 500
Adding +50 mult here would give you 10x100=1000 points. Adding +50 chips will give you 60x50=3000 points.
Adding to the lowest of the two numbers improves your score the most. Especially early game, mult is much lower than chips, so you want to improve mult. However once you have some good mult jokers improving chips becomes important. Especially in high card based decks, where you get very few chips from your hand.
If the multiplier jokers come in, the picture can change again. It makes adding mult more valuable because the addition will be multiplied.
I'm pretty sure that was in God Emperor. Heretics is the one where that same man acquires super sex powers that are so powerful he can overwhelm the sex powers of a clan of violent sex women and subjugate them to his will.