Help with Autoflower lighting?

Well I've got 4 Purple Kush Auto Feminized seeds growing. I started one of them a week earlier then the rest. That one will be two weeks old tomorrow and the others a week old. I was wondering I've been running them on 24 hours right now and if it would do any harm by switching them to 20/4 schedule by say week 3 for the first planted seed? I just wanted to make the switch to save the 4 hours of lighting. Would appreciate any advice =)

Dont think it matters when you switch em. They will live out their predetermined life no matter what cycle. I'm getting 3 auto freebies soon and will use 20/4 also. good luck