The extra step may seem to be extraneous, but during the interpositive stage there exists the possibility of burning and dodging, retouching, and contrast adjustment that is not as easily done with the reversal process of enlarging negatives. I am working on contact printing my 4X5 negs to a 4X5 interpositive and then enlarging onto half tone film. The rational is that the contact process in the interpositive stage realizes more of the original negative information. Additionally by doing it this way one only uses one large sheet of film in making the enlarged negative. Good luck and please keep us informed of your experience in enlarging negatives.