This word is one of the very few which are listed in their plural form in this dictionary, because that's the way it was provided and how it's usually used. This word has caused some discussions because it does not represent a building, it stands for a "collection of rooms". The plural form "hotels" is certainly not mebpa'mey-mey. mebpa'mey means "guest rooms," and both one hotel and multiple hotels can be described as guest rooms.
The reason we have mebpa'mey in the word list is not because Marc Okrand wanted to tell us that mebpa'mey means "hotel"; it's because he wanted to tell us that the way you say "hotel" in Klingon is mebpa'mey. He does that all the time in the English—Klingon lists: include a word that he expects people to try to look up but which aren't root words in Klingon.