You were having some issues a month or so ago with him peeing frequently in the evening, weren't you? Dry at lunchtime, wet when you got home in the afternoon and then the pee parade was on for the rest of the evening? Did that get resolved? Have you asked his vet about how frequently he seems to go, just to make sure there was no UTI or other issue?
By 4 months, most of our pups have been able to sleep through the night without a potty break. My feeding times are similar but I do not restrict water in the evening. Does he go out right before bedtime and you give him enough time to empty out? He gets plenty of exercise time between when you get home and bedtime? Does he get a bedtime snack, in case he's actually waking up a little hungry but as long as he's up, let's go outside, Mom! What would happen if you did not take him outside every time he wakes up? Just trying to see if there's anything to change, since everything you've said sounds like you're doing the right thing.