What'd I do wrong?

[monterey]

This question is sorta for Kenny.  I looked at the form building on the website and saw that it was pretty much what I had done previously.  BUT!!!  My top and bottom forms did not match.  One had considerably more curvature to it than the other.  I used the template and basicly cut the form out with one cut.  Izzat wrong??  I expected the two halves to match up perfect but they don't.