I understand. I would hesitate to feed a layer feed at 8 weeks and older due to the higher calcium content, but if this is the breeder you are getting them from, then following their recommendations is probably the best.
I might consider using a 14-16% grower/finisher with a lower calcium than...
Perhaps someone like @centrarchid @nicalandia @Pyxis @MysteryChicken can assist you with how you need to feed.
Not sure what you have read and what's consider a "low protein diet". Do you have links to that info?