The "Astor suite" is a somewhat ambiguous term. The only way that we which passengers had what cabins is from the Cave list, posted on this site. The Cave list was a list of 1st class cabin assignments that was found on the body of steward Herbert Cave. Unfortunately, this list was of passengers who booked early and thus is only half complete. While the Astors did book in time to make the list, they do not appear on it.
We know that Ismay had B 52-56, the Cardezas had B 51-55, and the Struasses had C 55-59. That leaves the other C Deck parlor suite open. It's always been assumed that the Astors were located in that suite. That suite was not explored by the recent expedition. However, it is very possible that they were not in that suite. My personal belief (although some disagree) is that they could not have been there. Fr. Browne's photograph taken from the B Deck entrance along the side of the ship shows some of the portholes belonging to that suite open. To me, this indicates that someone was already occupying that suite. However, this photo was taken at Southampton and the Astors didn't board until Cherbourg. If they were not in the other parlor suite, there are many other smaller (but no less ornate) suites on both B Deck and C Deck that are unaccounted for.
But who knows? For all we know they could have chosen more discreet accommodations on any deck. Many other wealthy passengers who certainly could have afforded suites chose small and simple cabins (the Lord and Lady Duff Gordon were in two tiny cabins on A Deck, for instance). It's possible that the Astors made a similar economic decision.
I'm a bit late here, but thought I'd add anyway. It has been assumes that the Astors were in C62 and C64 with the servants nearby and a nurse in C45. I don't doubt that they were there, in fact they also occupied cabin C66. However, considering that they do not appear on the Cave list, where C62 etc. originated from I have no idea.
David, that the windows in the Fr. Browne photo were open at Southampton means nothing. They could well be airing out, or open for any other reason. There were many windows of occupies cabins closed and open, and many empty (or believed to be empty) cabin windows also open and closed. Just looking at whether a porthole was open or closed means absolutely nothing, and has no relevance to its occupancy.