[Bowas]

As Mike Blume pointed out, one point in the case against dual fulfillment is found within the scriptures themselves.
This passage is clear, whichever time this is referring to, will be the worst...ever, as it is impossible to have two or more worst of anything.

This tribulation will be of such magnitude that there was never anything like it prior to it, nor will there be anything worse than it once it has occurred.

21 For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be.