These produce a bud at the base of each extending frond, and that's it, until the frond starts lignifying. Then it will start producing buds along the newly lignified piece that you can cut back to for ramification. If you pinch off the ends of the new growth, typically it'll just push that bud at the base next year and drop the frond that you pinched, essentially starting the process over. Better to let them grow more than you'd like and wait until you have the buds to cut back to if you're looking for ramification.