Hello there, and a warm welcome to Flyertalk and the Japan Forum, ymc1234.

Unfortunately, I can't see how you could get a meaningful answer to your question.

I've often booked hotels 4 months (and more in advance) just as I have flights. Sometimes this can yield better offers than booking nearer the time. Sometimes it doesn't.

Without knowing what the rates you got for these properties were, I can't see how anybody could speculate on whether you should hold on for a better deal.

Both Hotels are decent properties in convenient locations (although I wouldn't recommend staying at the ANA unless you are on the Club floor).

Another tip before committing to the ANA Tokyo IC involves what kind of temperature you consider comfortable for a hotel room. The ANA has a policy of not allowing guests to control the air conditioning during their undisclosed 'Spring' and 'Autumn' periods. The windows do not open and the rooms can become stifling and stuffy. If 27C and above is too warm for you (it certainly was for me) check with the Hotel first to find out if this policy will be in operation during your stay there.