Basically, every other paradigm switch you do, you get a free set of attacks. Your attack bar would be fully charged.
So, a general flow would be...
BATTLE START
First set of attacks -> Paradigm Shift -> Use next set of attacks instantly -> Use another set of attacks with this same Paradigm - Paradigm Shift - use next set of attacks instantly -> use another attacks with this same paradigm - Paradigm Shift - repeat
It has to be every other paradigm shift to work, if you just paradigm shift after every attack it won't work properly and will waste time.
Additionally, if you're good at it, you can paradigm shift at the start of the last attack animation of your lead character, and you won't have to watch the paradigm shifting animation, saving you time and "money."