You can have endeless combinations of "End's of Time Prophecy" by jumping from one scripture to another, from the Old Testament to the New!!! And imagine WT does not accept the traditional version of the Bible(79 Books) with another 10 books in the Old Testament, so I can guess how many combinations they could come up...
So since the WT is so focus with types and anti-types, first fullfilment and second, etc, etc. For them they just cannot have one prophecy and finished, like the prophecy of Daniel. They always come up with endless prophecies just to support their authority over 7,000,000 Jw's.