hi there
I think you could first try and see if 4hrs EASY affects his night time sleep and if you see it does, then I suggest you give DF another try. no later than at 11pm.
I'm writing this because in BWSAYP Tracy has written:
"Some infants are harder to tank up than others. They might take early evening feed but not take a dream feed. If that describes your baby, concentrate on the dream feed only."
It can be hard to teach your baby to take DF but it's achivable- and I know because my dd would not take a DF at all until she was some 4,5months and I decided I'd had enough of 1 or 2am feed and worked on DF. and it did work, she was sleeping through and we were both happy.
good luck
monika