Night feed timing

We’re sleep training our 5mo after a brief intermission from our first attempt because he had a cold. I’ve kept one feed in the night because previously he was nursing every hour so I didn’t want to go cold turkey in case he was legitimately hungry. The first two night he woke at 2am for a feed, tonight though he woke at 1:30 so I let him CIO. He woke again at 3:20 and I fed him. So does that time become his new feeding time? I read in 12hrs by 12weeks book that you should never go backwards with the time you feed at night, only spring forward and eventually it will become his morning feed. Any advice on if now sticking to the 3:20am feed time is the right thing to do? Thanks mamas