I tend to feel that the first inch of a cigar is often not as good as "once it gets going" and the last inch and a half can get bitter. So if you take a 6 inch cigar that has a sweet spot of 3 1/2 inches, you may just end up with two cigars with a sweet spot of 1/2 inch. So a one hour cigar may get you two 15 minute cigars when cut in half.
I know that on many cigar blends they change the bled for each vitola, and I'm guessing it is for good reason.