That's depends on your goals. Either way start looking into intermediate exercises and continue with the routine for now til you have formulated a more upgraded routine and stick with it for a few months before you change it up so you know what is working and what is not.
You add new exercises, you experiment with new techniques & you observe how your penis responds.
What works for some other guy, may not work for you.
As you add in new exercises, you should do so gradually - treating each new exercise as if you were a beginner. Yes - you have conditioned you penis generally, but any new exercise will shock your penis - so introduce it gradually to avoid injury.
Warm up > Side-side stretches > Squeezes > Edging > Warm down.
You'll want to start small and work your way up to a max of 1000 side-sides and 80 squeezes by doing a 1-2% load increase at each workout.
maybe do this 3 or 4 times a week.
But if you've seen gains from your JP90, there's no reason to change it. Don't fix what isn't broken.