I find I have to do an extra wrap around my ndl at the color-change edge to give me the right amt of slack. Otherwise, just seems I can't get enough stretch in the wrapped edge.
Are you actually picking up for the band or making it separate and attaching it? The front band is usually tensioned somewhat to prevent sag/stretch so ultimately you may not notice a big diff. If you're seeing a huge disparity between the two, however, you might find the two fronts end up diff lengths. Over time, the unwrapped would eventually grow while the wrapped most likely wouldn't.
Hopefully others who have more experience with color work will offer insights.