do not smoke the hive, open it quickly and set the feed on top of the frames. some breeds of bees will go through stores quicker than others in the fall months. the bottom deep is most likely empty, or with little in it, and like zoo said, they will not go back down for it. learning to heft the hives and guaging the weight is a good practice to learn, however, bees can still cold starve with a top deep full, and inches away from frames of honey. up here, i wouldn't say they were in trouble being in the top deep, (unless there is nothing in there) the cluster will expand between the bottom and top, and then the top, most of mine are pretty much in the top i think, (listening to the hives, can't open). i keep russians, very conservative on stores. if you are concerned about the stores, it does no harm to add fondant or winter patties directly on top the frames; i am not a fan of candy boards in our climate. the candy board, although with feed in it, is a barrier, they have to crawl up through whatever hole in the candyboard to access, whereas feed directly over the cluster is in direct access, directly over them.
ps bees are much cold hardy than we think they are. don't disturb the cluster, and you will be fine. have added feed on top of frames at 35 degrees.