The 4 hour routine never worked for us until she was 6mths old (regardless how many times Plunket told me that was the "right" thing for her *rolls eyes*)
You know your child better than Plunket and you will know his tired signs and hunger signs! I'd just go by that and what suits you guys.
If Plunket keep insisting on the 4 hour routne, tell 'em that's what you're doing anyway
P.S
Can you tell I'm not a Plunket fan?

I hate the way they apply the same rule to every baby!